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A Study of the Hydration of the Alkali Metal Ions in Aqueous Solution

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Department of Chemistry, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
*E-mail: [email protected]
Cite this: Inorg. Chem. 2012, 51, 1, 425–438
Publication Date (Web):December 14, 2011
https://doi.org/10.1021/ic2018693

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Abstract

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The hydration of the alkali metal ions in aqueous solution has been studied by large angle X-ray scattering (LAXS) and double difference infrared spectroscopy (DDIR). The structures of the dimethyl sulfoxide solvated alkali metal ions in solution have been determined to support the studies in aqueous solution. The results of the LAXS and DDIR measurements show that the sodium, potassium, rubidium and cesium ions all are weakly hydrated with only a single shell of water molecules. The smaller lithium ion is more strongly hydrated, most probably with a second hydration shell present. The influence of the rubidium and cesium ions on the water structure was found to be very weak, and it was not possible to quantify this effect in a reliable way due to insufficient separation of the O–D stretching bands of partially deuterated water bound to these metal ions and the O–D stretching bands of the bulk water. Aqueous solutions of sodium, potassium and cesium iodide and cesium and lithium hydroxide have been studied by LAXS and M–O bond distances have been determined fairly accurately except for lithium. However, the number of water molecules binding to the alkali metal ions is very difficult to determine from the LAXS measurements as the number of distances and the temperature factor are strongly correlated. A thorough analysis of M–O bond distances in solid alkali metal compounds with ligands binding through oxygen has been made from available structure databases. There is relatively strong correlation between M–O bond distances and coordination numbers also for the alkali metal ions even though the M–O interactions are weak and the number of complexes of potassium, rubidium and cesium with well-defined coordination geometry is very small. The mean M–O bond distance in the hydrated sodium, potassium, rubidium and cesium ions in aqueous solution have been determined to be 2.43(2), 2.81(1), 2.98(1) and 3.07(1) Å, which corresponds to six-, seven-, eight- and eight-coordination. These coordination numbers are supported by the linear relationship of the hydration enthalpies and the M–O bond distances. This correlation indicates that the hydrated lithium ion is four-coordinate in aqueous solution. New ionic radii are proposed for four- and six-coordinate lithium(I), 0.60 and 0.79 Å, respectively, as well as for five- and six-coordinate sodium(I), 1.02 and 1.07 Å, respectively. The ionic radii for six- and seven-coordinate K+, 1.38 and 1.46 Å, respectively, and eight-coordinate Rb+ and Cs+, 1.64 and 1.73 Å, respectively, are confirmed from previous studies. The M–O bond distances in dimethyl sulfoxide solvated sodium, potassium, rubidium and cesium ions in solution are very similar to those observed in aqueous solution.

Synopsis

The hydration of alkali metal ions has been studied by large angle X-ray scattering, LAXS, and double difference infrared spectroscopy. The obtained M−O bond distances from LAXS have been compared to relevant crystal structures, conclusions about hydration numbers in aqueous solution have been made, and new ionic radii have been proposed. Hydration numbers of six, seven, eight and eight are proposed for the sodium, potassium, rubidium and cesium ions in aqueous solution.

Introduction

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The sodium and potassium ions are among the most important metal ions in biology as well as industry. Aqueous solutions in living systems contain appreciable amounts of these ions, and their concentrations in living cells are regulated by intricate control systems, such as the sodium–potassium pump, which also play an important role in transmitting nerve signals. (1) Their importance in biology is reflected by their high abundance in living systems and in nature in general. Sodium and potassium ions are key constituents of many minerals, and their general high solubility is responsible for the composition of marine water. Abundance, high solubility and reaction inertness are desirable properties in industrial processes where they are frequently used as counterions for anions with desirable properties. The importance of lithium in the society is steadily increasing, especially in the area of rechargeable batteries. (2) Other industrial applications to be mentioned are lithium stearates for grease production, metallic lithium for high strength low weight alloys, lithium carbonate in the glass and porcelain industry, and applications in psychiatric medicine. (3) On the other hand, the use of rubidium and cesium is presently more limited in society. Accidental and intentional emissions of radioactive cesium isotopes from nuclear industry and testing of weapons have caused an environmental problem. (4) In spite of many conducted studies the knowledge of the structures and bonding properties of the hydrated alkali metal ions in aqueous solution is scarce and deviating. The structures of hydrated metal ions in aqueous solution have been reviewed by several authors. (5-9)
The frequently high solubility of alkali metal salts in water is due to large entropies of solution while heats of solution often are endothermic, as for example sodium chloride. (10) This shows that the alkali metals are weakly hydrated, the heats of hydration are small, (11) and they have a tendency to disrupt the aqueous bulk structure without ordering the water molecules as the highly charged metal ions do through strong hydration. Hydrogen bonding is very important at the description of the hydration of chemical species. It is well-known that ions affect the network of hydrogen bonds making up the bulk structure of water. In order to systematize the way ions affect the hydrogen bonds in the aqueous bulk, the concept of structure making and structure breaking ions has been introduced. (12) Originally referring to increased or decreased viscosity in the vicinity of ions, (12) the concept has been interpreted in somewhat different ways. Marcus reviews the subject considering e.g. reorientation times, and thermodynamic as well as spectroscopic parameters as indicators. (6)A common view of the structure making and breaking properties is the difference in hydrogen bonding around the ion under study. (6) The structure of liquid water can be viewed either as a mixture of hydrogen bound and interstitial water molecules (6)or as primarily hydrogen bound structure with hydrogen bonds of varying strength. (13) The latter view is supported by the fact that the broad distribution of angles and distances in bulk water can only be compared to arbitrary definitions of hydrogen bonds. (13) It can be concluded that small highly charged ions are structure makers while large ions with low charge density, such as the perchlorate ion, are definite structure breakers. (6) Soper et al. have pointed out that the structure maker/breaker concept is unfortunate in the sense that small highly charged ions are considered structure makers while they are actually breaking the hydrogen bonds of the aqueous bulk to form even stronger ones in the close vicinity of the ion. (14)
It is proposed that the double difference infrared (DDIR) spectroscopy method offers a possibility to study the structure making or breaking properties of solvated ions as defined by whether hydration shell molecules interact more strongly or more weakly with water molecules than bulk water molecules interact with each other. (15) By comparing the O–D oscillation energy of HDO molecules in the hydration shell of an ion or molecule with those in the aqueous bulk, the relative behavior of the hydration shell molecule can be investigated. An O–D stretching frequency lower than in bulk water has been interpreted as belonging to structure making ions, as defined above, while ions or molecules which increase the O–D stretching frequency in their hydration shell are considered as structure breakers. (15) The concept of negative hydration is equivalent or closely related to the term structure breaker. (16)
The DDIR method was introduced by the Lindgren group (17-26) and further developed and applied by the Stangret group. (15, 27-35) The foundation for this method is the rule of Badger and Bauer, (36) stating that the position of the O–D stretching vibration in monodeuterated water is affected proportionally to the energy of hydrogen bonds. By taking a series of differences between experimental infrared spectra of a solute dissolved in pure water, and in water containing ca. 8% HDO, a spectrum representing the O–D stretching vibrations of water molecules in the hydration shells is obtained. (17) This spectrum, representing the water molecules affected in such a way that it is significantly different from the spectrum of pure water, is divided into contributions from waters binding to one or several solutes. One conclusion from the experiments performed so far has been that anions affect the peak position of the O–D stretching vibration in HDO in a continuous manner, while the same vibration of the water molecules hydrating cations tends to group at certain levels. (15, 31) The position of the O–D stretching vibration of HDO molecules in the second hydration shell of di-, tri- and tetravalent metal ions is thought to approximately coincide with the values of the first hydration shell water molecules of alkali metal ions. (15) In the hydration shell of ions or molecules, HDO molecules whose O–D stretching vibration is located at lower wavenumbers than 2509 cm–1 form stronger hydrogen bonds than those within the aqueous bulk. The opposite is assumed for hydrated species where HDO molecules show an O–D stretching vibration at wavenumbers higher than 2509 cm–1. The general view so far is that most cations and anions with high charge density are structure makers, while monovalent anions are structure breakers. Exceptions to this rule of thumb are for example alkali metal ions such as potassium, rubidium and cesium as well as anions such as fluoride and hydroxide. (15, 33)
The sodium ion crystallizes with full hydration shell with large low-symmetrical counterions, Table S1b in the Supporting Information (SI), while in salts with small and symmetric anions the lattice energies favor crystallization with the anhydrous sodium ion. The hydrated disodium ion, [Na2(H2O)10]2+, is observed in several solid compounds, as well as other hydrated polysodium ions, Table S1b in the SI. However, these di- and polysodium ions have never been observed in aqueous solution. The hydrated sodium and polysodium ions have octahedral configuration in a vast majority of the structures reported in the solid state, Table S1b in the SI. In the same way the vast majority of the compounds containing hydrated lithium ions in the solid state are tetrahydrates with tetrahedral configuration. However, there are also examples of structures with six-coordinate lithium ions in endless chains of shared water molecules, Table S1a in the SI.
The strong relationship between ionic radius and coordination number was established in a thorough investigation by Shannon. (37) At the determination of structures in solution, independent of method used, the mean bond distances can be determined accurately, while the coordination numbers are less reliable due to the very strong correlation with the temperature factor/Debye–Waller coefficient. The mean bond distance in homoleptic complexes, e.g. pure hydrates or solvates, gives therefore a strong indication of the coordination number knowing the relationship between ionic radius and coordination number for the metal ion under study.
The alkali metal ions are spheres with low charge density forming mainly electrostatic interactions. As the alkali metal ions, except lithium, are large, the charge densities are low and the electrostatic interactions formed are weak as well as their ability to form covalent interactions due to filled outer electron shells. The inability of the potassium, rubidium and cesium ions to form well-defined hydrate and solvate complexes in the solid state is a clear sign of the weak hydration, and their hydrate structures must be determined in aqueous solution. The ionic radii of the lithium and sodium ions in different configurations can be accurately determined from the number of homoleptic complexes reported in the literature (ICSD and CSD). (38, 39) On the other hand, the ionic radii of the potassium, rubidium and cesium ions are much more difficult to extract as the number of complexes with a well-defined configuration and a nondistorted structure is very limited (ICSD and CSD). (38, 39) Only compounds as oxides, where the lattice energies are strong and the preferred coordination of the alkali metal ion can be suppressed, have been used so far to estimate the ionic radii of the alkali metal ions.
A large number of X-ray and neutron scattering studies and theoretical simulations have been performed on the hydrated lithium ion in aqueous solution. The spread in the data is very large, and the interpretation of especially X-ray data is difficult, almost impossible, due to the very weak scattering effect of lithium in such experiments. We have performed LAXS experiments on the hydrated lithium ion in this study, but concluded that the contribution from the electron-poor lithium ion is too small to obtain any significant information. Experimentally reported values of the Li–O distance in the hydrated lithium ion are e.g. 1.90, (40) 1.98 (41) and 2.17 Å, (42) of which ref 40 is a neutron scattering study while the other two used X-rays. Smirnov and Trostin have been reviewing available experimental data for the lithium ion, (43) and more information is available in general reviews. (6, 7, 44, 45) It is not possible from the present knowledge to unambiguously decide the coordination number of the hydrated lithium ion in aqueous solution based on present experimental data. Neither do the reported simulation studies on the hydrated lithium ion in aqueous solution give a conclusive picture. Simulation studies have reported Li–O bond distances of 1.95, (46) 1.97, (41) 1.971 (47) and 2.03 Å. (48) For the lithium ion, the suggested hydration number is usually four. (40, 42, 46, 49) The review article by Smirnov and Trostin gives a thorough collection of hydration studies of the lithium ion, whereof some suggest the coordination number six. (43)
The experimentally determined Na–O distance in the hydrated sodium ion in aqueous solution is in a wide range as well, e.g. 2.34, (50) 2.40, (51) 2.42 (42) and 2.50 Å. (52) A recent computer simulation by Azam et al. predicts a Na–O distance of 2.34/2.36 Å, (53) and older simulations have reported values in the same order. (54, 55) For the sodium ion, the hydration number has been suggested to be four, (41, 51, 56) 4.6, (57) 5.3, (50) 5.5, (53) 5.6/6.5, (54) six, (58) 6.5 (55) and eight. (52) The available experimental data for the hydrated sodium ion in aqueous solution has been reviewed. (59)
Experimental values of the K–O bond distance in the hydrated potassium ion in aqueous solution are in the range 2.65–2.97 Å. (14, 42, 50, 52, 57, 60) A computer simulation by Azam et al. predicts a K–O distance of 2.80 Å, (53) and a previous investigation from the same laboratory came to a similar conclusion, 2.78–2.81 Å. (54) The hydration number of the potassium ion in aqueous solution has been suggested to be 5.6/3.3, (57) six, (14, 50) 6.2/6.8 (53) and 7.8/8.3. (54)
A combined LAXS and EXAFS study of the hydrated rubidium ion determined the Rb–O bond distance in the hydrated rubidium ion in aqueous solution to 2.98 Å. (61) Other Rb–O bond distances reported from experimental studies are 2.83, (62) 2.90 (63) and 3.05 Å. (64) In a QM/MM simulation study the Rb–O bond distance of the hydrated rubidium ion was predicted to 2.9 Å (65) and in a study with ab initio based model potentials to be 2.95. (66) The hydration number of the hydrated rubidium ion is reported to be six, (62) 6.9, (64, 65) 7.1 (66) and eight. (58, 61)
The reported Cs–O bond distances in the hydrated cesium ion from experimental studies are in the range 2.95–3.21 Å; (40, 42, 57, 67) the value 2.95 Å of ref 40 has been misquoted in review references. (42, 44, 57, 59) In a QM/MM simulation study three different simulation approaches were utilized, with the one yielding a Cs–O bond distance of 3.20 Å being regarded as the most reliable one, (68) while another simulation study suggests 3.10 Å. (69) The cesium ion is the alkali metal ion with lowest charge density and is therefore expected to affect the water matrix less than the other ions. At the same time its larger size opens up the geometrical possibility of a higher coordination number than eight. (44) The coordination number of the hydrated cesium ion has been suggested to be eight, (40, 49, 58) 8–9 (68) and 8/6.5, (69) while the low value 3.6 (57) seems unrealistic. Smirnov and Trostin have reviewed available experimental structure data in aqueous solution for the potassium, rubidium and cesium ions. (70)
There is a general agreement that the potassium, rubidium and cesium ions are structure breakers, and that the lithium ion is a structure maker. (6) Opinions on whether the sodium ion decreases or increases the amount of hydrogen bonding differs somewhat, and Marcus assigns it as a borderline ion. (6) Scientists working with computer simulations frequently report second and third hydration shells, as well as hydration shells even further from the central atom, utilizing the next-neighbor approach. However, in our context a hydration shell is only present if the included water molecules are structurally or spectroscopically distinguishable from bulk water. There is a general agreement that the potassium, rubidium and cesium ions are lacking a second hydration sphere due to their low charge density. (6, 59)For the lithium ion, a second hydration sphere has been reported by some authors but not by others. (43) Even though the existence of a second hydration sphere of the lithium ion has been considered likely, there is yet no consensus regarding its composition. (43, 44) Whether a second hydration shell around the sodium ion is present or not is a difficult task to solve, but some authors propose that such a second hydration sphere should be present. (5, 70) The reorientation times of water molecules in the first hydration shell decrease down the alkali metal group, with the hydrated lithium and sodium ions having longer reorientation times than in bulk water, supporting structure maker properties, while the opposite is true for the hydrated potassium, rubidium and cesium ions. (16, 70, 71) These data are consistent with the assignment of structure makers and breakers according to Marcus, (6) also indicating that the sodium ion should be a weak structure maker.
Structural studies of the hydrated alkali metal ions in aqueous solution are difficult due to the weak hydration causing weak metal ion–water bonds. This makes EXAFS as a method less suitable due to the low sensitivity for long distances with large Debye–Waller factors. On the other hand, large angle X-ray scattering, LAXS, easily detects such distances. (72) The drawback with LAXS is that all distances in the studied sample are included in the experimental data which in reality implicate that high concentrations are required, and that distances within the solvent may hide other relevant distances such as those between solute and water. The K–O, Rb–O and Cs–O bond distances are similar to the O···(H−)O distances in the aqueous bulk making data analysis challenging. In order to support the studies in aqueous solution, LAXS studies have been performed in the aprotic solvent dimethyl sulfoxide, Me2SO. The advantage with this system is that it lacks such intermolecular solvent distances in the region of the K–O, Rb–O and Cs–O bond distances. The coordination numbers of hydrated and Me2SO solvated metal ions are often the same, or at least very similar. (73) The coordination number is normally difficult to determine from measurements in solution, where the primary structure information is one-dimensional, as the correlation between temperature factor coefficient and number of distances is strong and cannot the be determined accurately without putting one of these parameters to a fixed value. On the other hand, distances are accurately determined by these methods, and as the correlation between ionic radius and coordination number is strong, very good predictions of the coordination number can be made from the obtained M–O bond distance. The ionic radius of a metal ion is preferably evaluated from homoleptic complexes of neutral ligands as discussed in detail below.
The aim of the present study is to determine the M–O bond lengths in the hydrated alkali metal ions in aqueous solution by means of LAXS measurements, as this is the experimental method most suitable to determine long distances with broad bond distance distribution. (72) Complementary studies have been performed on dimethyl sulfoxide solvated alkali metal ions as dimethyl sulfoxide is expected to form solvate complexes similar to the hydrates, but as dimethyl sulfoxide is aprotic, no solvent–solvent distances are present close to the M–O ones, as in water. Crystallographic data of alkali metal ion complexes with oxygen donor ligands have been collected from structure databases, (38, 39) and the relationship between M–O bond length and coordination number/configuration has been analyzed. With this as a basis, coordination numbers of hydrated alkali metal ions can be estimated from experimentally obtained M–O bond distances. This material also makes it possible to predict more accurate ionic radii of the alkali metal ions with different coordination numbers than before. The O–D stretching vibrations of the monodeuterated water molecules different from the bulk water have been determined by the DDIR method in order to describe the bonding properties of the water molecules binding to the alkali metal ions in as great detail as possible.

Experimental Section

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Chemicals

The following chemicals have been used in the experiments: Milli-Q filtered deionized water, heavy water, D2O, (99.96 atom % D2O, Aldrich), sodium iodide, NaI (99.99%, Aldrich), potassium iodide, KI (99.5%, Merck), rubidium iodide, RbI (99.9%, Aldrich), cesium iodide, CsI (99.9%, Aldrich), lithium hydroxide, LiOH (99.9%, Aldrich), cesium hydroxide, CsOH (99.95%, Aldrich), lithium perchlorate, LiClO4 (99.99%, Aldrich), sodium perchlorate, NaClO4 (99.99%, Aldrich), and dimethyl sulfoxide, (CH3)2SO, (99.8%, Aldrich). All chemicals were used as purchased. Composition, concentration and density of the prepared solutions are summarized in Table S2 in the SI. Zero point solutions of deionized water containing ∼8% HDO were obtained by mixing water and heavy water. In order to minimize conversion of iodide to triiodide, exposure to daylight was minimized during the preparation and storage of the cesium and rubidium iodide solutions.

Large Angle X-ray Scattering

The scattering of Mo Kα X-ray radiation (λ = 0.7107 Å) from the free surface of the studied solutions was measured by means of a large angle θ–θ diffractometer at ca. 450 discrete points in the range 1 < θ < 65°; the scattering angle is 2θ. The solutions were contained in a Teflon cup inside an airtight radiation shield with beryllium windows. The scattered radiation was monochromatized in a focusing LiF crystal monochromator. At each preset angle 100,000 counts were accumulated and the entire angular range was scanned twice, which corresponds to a statistical error of about 0.3%. The divergence of the primary X-ray beam was limited by 1 or 1/4° slits for different θ regions, with partially overlapping data for scaling purposes. The experimental setup and the theory of the data treatment and modeling have been described elsewhere. (74) The data treatment was carried out by means of the KURVLR program. (75) The experimental intensities were normalized to a stoichiometric unit of volume containing one alkali metal atom, using the scattering factors f for neutral atoms, including corrections for anomalous dispersion, Δf′ and Δf′′, and for Compton scattering. (76, 77) Least-squares refinements of the model parameters were carried out by means of the STEPLR program, (78) where the expression U = ∑w(s)[s·iexp(s) – s·icalc(s)]2 is minimized; the scattering variable s = (4π/λ)sin θ and w(s) a weighting factor. The refinement of the model parameters was made for data in the high s region, 4.0–16.0 Å–1, for which the intensity contribution from the long-range distances can be neglected. A Fourier back-transformation procedure was used to improve the alignment of the experimental structure-dependent intensity function iexp(s) before the refinements, by removing spurious nonphysical peaks below 1.2 Å in the radial distribution function. (79)

Double Difference Infrared (DDIR) Spectroscopy

The infrared spectroscopy measurements were performed on a Perkin-Elmer Spectrum 100 FT-IR spectrometer. The sample was kept between CaF2 windows separated by a Teflon spacer. Path lengths were determined interferometrically to 32.8, 33.2, 32.9, 33.1, and 32.6 μm for the aqueous solutions of LiClO4, NaI, NaClO4, KI, RbI and CsI, respectively. The temperature was kept at 298.2 ± 0.1 K by an electrically heated liquid cell temperature controller from Pike Technologies. The beam diameter was set to 3 mm, and 256 scans were collected in the range 3500–900 cm–1 with a resolution of 4 cm–1. Spectral treatment was performed in accordance with the method developed by Lindgren et al. (17) Removal of bulk water was performed in accordance with an algorithm developed by the Stangret group. (27, 29) This algorithm utilizes measurements at several concentrations to obtain a derivative of absorbance with respect to concentration. The affected spectrum extrapolated to infinite dilution (εa) is obtained from the derivative, the bulk water spectrum (εb), the mean molar mass of the solvent, ca. 8% HDO in water (M) and the affected number of water molecules (N):(1)The way the number of affected water molecules is calculated is described elsewhere. (27, 29) The absorption bands related to the water molecules affected by the ions are compared to the band of pure water, and their relative positions implicate how the aqueous structure is affected. In Figure 1 it can be seen that a strong energy rich O–D bond (Figure 1c), corresponding to a high wavenumber, causes a weak O···D–O bond. The spectral treatment has been performed with the spectroscopy software program GRAMS/AI 8.0 from Thermo Electron Corporation and its add-in Razortools from SpectrumSquare. The additional add-in program Yanuz from the Stangret group has also been used to obtain the derivative with respect to concentration.

Figure 1

Figure 1. (a) HDO in bulk water, νO–D = 2509 cm–1, dO(···D)–O = 2.89 Å. (b) HDO affected by a structure making cation, νO–D < 2509 cm–1, dO(···D)–O < 2.89 Å. (c) HDO affected by a structure breaking cation, νO–D > 2509 cm–1, dO(···D)–O > 2.89 Å. O–D bond strength is indicated by the line thickness, and orange color represent a D atom.

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Structure Databases and the Evaluation of Ionic Radii

In the search for relevant solid state structures, the databases Inorganic Crystal Structure Database (38) and Cambridge Crystallographic Data Centre (39) were used. As the collection of structures was diverse, it was found necessary to categorize them before judging their relevance. This categorization is described in Appendix 3 in the SI.

Results and Discussion

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Analysis of Most Reliable Ionic Radii of the Alkali Metal Ions for Different Coordination Numbers

For the lithium and sodium ions, the available crystal structure material is sufficient for an accurate determination of the ionic radii in several configurations. In order to get a fair view of the ionic radii of the alkali metal ions it is important to select structures where the influence from lattice energies is as small as possible. Previously proposed ionic radii are based on oxide and fluoride structures, (37) where the close-packing of the anions is a strong driving force for their structures, while the preferred configuration of especially ions with low charge density, as the alkali metal ions, is suppressed. A number of structures of alkali metal compounds have in the present study been discarded due to repetitive measurements (R), suspicion of nonoxygen bonding (N), shackled structure (S) or failure of passing Grubbs statistical test (G), Appendix 1 in the SI. It has been assumed that structures, where the longest bond is no more than 10% longer than the shortest one, have a sufficient low constraint and are representative for a certain configuration. These structures are hereafter referred to as approved structures, and are given in Tables S1a–S1e in the SI together with considered but nonapproved structures of the various classes.
Considering the lithium ion, two groups of complexes with oxygen donor ligands have been identified as relevant: (i) neutral homoleptic hydrates, Figure 2, and (ii) complexes with neutral non-ether monodentate ligands, Figure 3. A summary for coordination numbers four and six is given in Table S4 in the SI, and the influence of data selection on average M–O bond distances is shown as well. Classification has been made in accordance with the system presented in Appendix 3 in the SI. It can be noted that the M–O distances does not differ appreciably between the 36 four-coordinated complexes, 1.942 Å, belonging to group (i) and the 80 four-coordinated complexes of the expanded group (ii),1.941 Å. By subtracting the radius of the oxygen atom in coordinated water, 1.34 Å, (80) an ionic radius of 0.60 Å is obtained for the lithium ion in four-coordination, tetrahedral fashion. The mean Li–O bond distance in four-coordinated homoleptic tetrahydrofuran solvated lithium ions is 1.918 Å. By subtracting the ionic radius of the lithium ion obtained from hydrates, the radius of the oxygen in tetrahydrofuran coordinated to an alkali metal ion is estimated to 1.32 Å for the investigated complexes, Table S1a. A large number of 1,2-dimethoxymethane solvated lithium ions has been reported in the solid state, almost all being six-coordinate in octahedral fashion. In total 75 structures with a mean Li–O bond distance of 2.134 Å remain as approved with respect to bond length distribution. In a limited number of compounds containing hydrated lithium ion in endless chains with bridging water molecules the lithium ion is six-coordinate with a mean bond distance of 2.132 Å, Table S4 in the SI and Figures 2 and 3. This gives, assuming an oxygen radius of 1.34 Å also in these oxygen donor ligands, an ionic radius of the lithium ion in octahedral configuration of 0.79 Å. This is slightly longer than reported by Shannon, 0.76 Å. (37)

Figure 2

Figure 2. Crystal structures of neutral, homoleptic, Li+ hydrates. The dashed line is drawn between mean values for four- and six-coordination (geometrically approved atoms). Error bars correspond to two standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses.

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Figure 3

Figure 3. Crystal structures of neutral, monodentate non-ether Li+ complexes. The dashed line is drawn between mean values for four- and six-coordination (geometrically approved atoms). Error bars correspond to two standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses.

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The mean Na–O bond distance in five- and six-coordinate neutral homoleptic sodium complexes is 2.358 and 2.412 Å, respectively, Figures 4 and 5, Table S5 in the SI. This gives ionic radii of the sodium ion of 1.02 and 1.07 Å in five- and six-coordination, respectively. These ionic radii for the sodium ion are significantly larger than those proposed by Shannon. (37) This is probably due to large lattice effects in the oxide and fluoride compounds Shannon used in his analysis. The average Na–O distances in the THF solvates are 2.324 and 2.395 Å in five- and six-coordination respectively, and an oxygen radius for THF of 1.32 Å, as described above, gives the very same ionic radii of the sodium ion as other oxygen donor ligands.

Figure 4

Figure 4. Crystal structures of neutral, homoleptic, Na+ hydrates. The dashed line is drawn between mean values for five- and six-coordination (geometrically approved atoms). Error bars correspond to ±2 standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses. A green circle represents the experimental M–O distance determined by LAXS for six-coordination in this study.

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Figure 5

Figure 5. Crystal structures of neutral, non-ether, monodentate Na+ complexes. The dashed line is drawn between mean values for five- and six-coordination (geometrically approved atoms). Error bars correspond to ±2 standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses. A green circle represents the experimental M–O distance determined by LAXS for six-coordination in this study.

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In an attempt to follow the order of priority it was found that no relevant homoleptic hydrates was found for the potassium, rubidium and cesium ions, with the exception of the unreasonably short K–O bonding in the hexaaquapotassium dihydroxy-(2-guanidino-1-benzimidazole-N,N′)borate monohydrate. (81) Therefore, it is necessary to rely on structures with less desirable features such as anionic ligands, heteroleptic complexes or multidentate ligands for the larger alkali metal ions. For the heavier alkali metal ions the lack of homoleptic hydrates is well in line with these ions' low charge density. If one would accept anionic, heteroleptic and multidentate ligands, they are still so few that it is difficult to make a proper analysis, as illustrated in Figures S2–S4 in the SI, and any safe conclusions cannot be drawn. Still, two features should be noted. First, the absence of homoleptic hydrates in the solid state underlines the weak hydration of the larger alkali metal ions. Second, the deviation from the ionic radii proposed by Shannon is noticeable. As Shannon used highly charged oxides for radius determination, the lattice energies are much stronger than M–O bond energies, and the alkali metal ions get a coordination environment controlled by close-packing and lattice energies, which has little significance at the discussion of ionic radii in a nonlattice environment as complexes in solution. Ions in an oxide matrix may have an increased or reduced size relative to the unconstrained species in solution, in order to fill available holes in a close-packed oxide matrix. Cations too large to reside in holes of a close-packed anionic matrix seek alternative arrangements, and this is the case of Rb+ and Cs+, which in fact are larger than the monatomic anions. The radius of six-coordinate K+ is in the same range as water oxygen and oxide oxygen, while the radius of K+ in seven-coordination exceeds both slightly. For six- and seven-coordinate K+, the radii proposed in this work are in agreement with those of Shannon, (37) Figures 6 and S2 in the SI. Values based on Shannon’s oxide and fluoride compounds are lower than those found in the crystal structure investigation for Rb+, and even more so for Cs+, Figures S3–S4 in the SI. This could be explained by an energetical driving force toward an equalized ionic size, suitable for stable non-close-packed crystal structures. From geometrical calculations it is found that the ratio between the radii of hypothetical hard-sphere cations and equally hypothetical hard-sphere anions must be below 0.732 for the former to fit into octahedral holes in a close-packed matrix of the latter. (82) Deviations from this principle occur as ions are in reality not hard spheres, and that close-packing of water molecules around an ion is merely an approximation of varying validity.

Figure 6

Figure 6. Crystal structures of potassium THF solvates. The error bar corresponds to ±2 standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses. The dashed line is drawn 0.02 Å above average values for six- and seven-coordination in order to correct for the smaller size of THF oxygen relative to water oxygen (see text). A green circle represents the experimental M–O distance determined by LAXS for seven-coordination in this study.

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Despite the objections regarding the cyclic ether tetrahydrofuran (THF) previously brought up, this compound may be useful in the study of potassium. The disadvantages found by Lundberg et al., (83) concerning small highly charged hard ions, should be less severe in this study of cations with lower charge density. The mean K–O bond distance for the tetrahydrofuran solvated potassium ion in six-coordination was determined to 2.70 ± 0.06 Å (17 structures), Figure 6, Table S1c in the SI, giving an ionic radius of 1.38 Å using an oxygen radius of 1.32 Å in THF, see above. Utilizing the known radius of coordinated water oxygen radius the expected K–O bond distance for a six-coordinate hydrated potassium ion is 2.72 Å. The only crystal structure of a seven-coordinate potassium tetrahydrofuran solvate has a mean K–O bond distance of 2.78 Å, corresponding to an ionic radius of the potassium ion of 1.46 Å, (84) giving an expected K–O bond distance in a seven-coordinate potassium hydrate of about 2.80 Å. Proposed ionic radii are summarized in Table 1.
Table 1. New Proposed Ionic Radii in Å of the Alkali Metal Ions
 4-coord5-coord6-coord7-coord8-coord
Li+0.60 0.79  
Na+ 1.021.07  
K+  1.381.46 
Rb+    ∼1.64
Cs+    ∼1.73

Structure Determination of the Hydrated Alkali Metal Ions in Aqueous Solution

The radial distribution functions (RDFs) from the LAXS experiments on the aqueous sodium, potassium and cesium iodide solutions reveal two peaks, two peaks and one peak below 4 Å, see Figures 7–9. The peak or shoulder at 3.5 Å corresponds to the I–O bond distance in the hydrated iodide ion, which is full agreement with previous reports. (8) The peak at 2.9 Å corresponds to an intermolecular O···O distance in the aqueous bulk, and to Cs–O and K–O bond distances in the hydrated cesium and potassium ions, respectively, Figures 7 and 8. The Na–O bond distance in the hydrated sodium ion is seen as a weak shoulder at ca. 2.4 Å, Figure 9. The RDF of the aqueous cesium hydroxide solution displays only one peak containing intramolecular O···O distances in the aqueous bulk, and the Cs–O bond distances in the hydrated cesium ion, Figure S5 in the SI. The obtained Na–O, K–O and Cs–O bond distances of 2.43, 2.80, and 3.07 Å, respectively, support six-, seven- and eight-coordination, respectively. These coordination numbers have been applied as fixed parameters in the final refinement of the structure parameters in the LAXS data. The refined M–O, I–O and O···O distances and the corresponding temperature factor coefficients are summarized in Table 2, and the fits of the experimental intensity functions are given in Figures 7–9 and S5 in the SI. The structure of the hydrated hydroxide ion indicates that it accepts strong hydrogen bonds from surrounding water molecules, which is in agreement with previous DDIR studies. (33)

Figure 7

Figure 7. (Top) LAXS radial distribution curves for a 2.001 mol·dm–3 aqueous solution of cesium iodide. Upper part: Separate model contributions (offset: 20) of the hydrated cesium ion (black line), the hydrated iodide ion (red line) and the aqueous bulk (blue line). (Middle) Experimental RDF: D(r) – 4πr2ρo (red line), sum of model contributions (black line) and the difference between experimental and calculated functions (blue line). (Bottom) Reduced LAXS intensity functions s·i(s) (solid line); model s·icalc(s) (dashed line).

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Figure 8

Figure 8. (Top) LAXS radial distribution curves for a 2.007 mol·dm–3 aqueous solution of potassium iodide. Upper part: Separate model contributions (offset: 12) of the hydrated potassium ion (black line), the hydrated iodide ion (red line) and the aqueous bulk (blue line). (Middle) Experimental RDF: D(r) – 4πr2ρo (red line), sum of model contributions (black line) and the difference between experimental and calculated functions (blue line). (Bottom) Reduced LAXS intensity functions s·i(s) (solid line); model s·icalc(s) (dashed line).

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Figure 9

Figure 9. (Top) LAXS radial distribution curves for a 2.007 mol·dm–3 aqueous solution of sodium iodide. Upper part: Separate model contributions (offset: 14) of the hydrated sodium ion (black line), the hydrated iodide ion (red line) and the aqueous bulk (blue line). (Middle) Experimental RDF: D(r) – 4πr2ρo (red line), sum of model contributions (black line) and the difference between experimental and calculated functions (blue line). (Bottom) Reduced LAXS intensity functions s·i(s) (solid line); model s·icalc(s) (dashed line).

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Table 2. Mean Bond Distances, d/Å, Number of Distances, N, Temperature Coefficients, b/Å2, and the Half-Height Full Width, l/Å, in the LAXS Studies of the Hydrated Alkali Metal Ions in Aqueous Solution at Room Temperature
speciesinteractionNdbl
Sodium Iodide in Water, 2.007 mol·dm–3
Na(OH2)6+Na–O62.43(2)0.025(2)0.22(1)
I– (aq)I–O63.549(9)0.0180(8)0.19(1)
water bulkO···O22.902(6)0.0220(10)0.21(1)
Potassium Iodide in Water, 2.002 mol·dm–3
K(OH2)7+K–O72.81(1)0.027(2)0.23(1)
I– (aq)I–O63.539(7)0.0186(7)0.19(1)
water bulkO···O22.889(7)0.0219(8)0.21(1)
Cesium Iodide in Water, 2.001 mol·dm–3
Cs(OH2)8+Cs–O83.081(1)0.031(2)0.25(1)
I– (aq)I–O63.555(7)0.0191(7)0.19(1)
water bulkO···O22.889(7)0.0212(8)0.21(1)
Cesium Hydoxide in Water, 1.802 mol·dm–3
Cs(OH2)8+Cs–O83.074(1)0.031(2)0.25(1)
OH– (aq)O···O52.73(2)0.008(2)0.13(1)
 O···O12.950.02250.21
water bulkO···O22.898(7)0.0202(8)0.21(1)

Structure of the Dimethyl Sulfoxide Solvated Alkali Metal Ions in Solution

The RDFs from the LAXS experiments on the dimethyl sulfoxide solutions of sodium, potassium and cesium iodide solutions reveal three peaks or two peaks and a shoulder (potassium) respectively at 1.5, 2.4–3.0 and 3.5–4.5 Å (Figures S6–S8 in the SI). The peaks at 1.5 and 2.5 Å correspond to intramolecular S–O, S–C and O–C bond distances in dimethyl sulfoxide. The peak at 2.4–3.0 Å has also a significant contribution from the M–O bond distance in the dimethyl sulfoxide solvated alkali metal ions. The peak or shoulder in the region 3.5–4.5 Å corresponds to M···S distances. There are no peaks or shoulders in the RDF which correspond to the dimethyl sulfoxide solvated iodide ion showing that there is no well-defined structure of dimethyl sulfoxide molecules around this ion. The obtained Na–O, K–O and Cs–O bond distances of 2.43, 2.80, and 3.06 Å support six-, seven- and eight-coordination, respectively. This is consistent with the results in aqueous solution, see above. These coordination numbers have been applied as fixed parameters in the final refinement of the LAXS data. The refined M–O and M···S distances, and the corresponding temperature factor coefficients are summarized in Table 3, and the fit of the experimental intensity functions are given in Figures S6–S8 in the SI. The M–O–S bond angles of 136.3, 137.4, and 134.2° for sodium, potassium and cesium, respectively, are typical for metal ions binding to dimethyl sulfoxide through mainly electrostatic interactions. (73)
Table 3. Mean Bond Distances, d/Å, Number of Distances, N, Temperature Coefficients, b/Å2, and the Half-Height Full Width, l/Å, in the LAXS Studies of the Dimethyl Sulfoxide Solvated Alkali Metal Ions in Solution at Room Temperature
speciesinteractionNdbl
Sodium Iodide in Me2SO, 1.017 mol·dm–3
Na(OSMe2)6+Na–O62.43(2)0.020(2)0.20(1)
Na···S63.70(2)0.040(2)0.28(1)
Potassium Iodide in Me2SO, 1.017 mol·dm–3
K(OSMe2)7+K–O72.790(7)0.0200(13)0.200(6)
K···S74.060(8)0.042(2)0.29(1)
Cesium Iodide in Me2SO, 1.000 mol·dm–3
Cs(OSMe2)8+Cs–O83.061(8)0.0234(8)0.216(4)
Cs···S84.279(7)0.056(2)0.33(1)

Analysis of Bonding Characteristics of Hydrated the Alkali Metal Ions in Aqueous Solution Using Double Difference IR

The affected spectra, obtained as outlined in the Experimental Section, were obtained for NaI (N = 9.6), KI (N = 10.6), RbI (N = 8.9), CsI (N = 7.4), LiClO4 (N = 10.3) and NaClO4 (N = 11.6). Each spectrum can be modeled from Gaussian peaks, which are supposed to represent anion and cation affected HDO. Two peaks are required to represent the cationic contribution of NaI, LiClO4 and NaClO4. The affected spectra for the investigated iodide salts are given in Figure 10 and for the perchlorate salts in Figure 11, and the peak positions are summarized in Table 4.

Figure 10

Figure 10. Affected spectrum for NaI(aq), KI(aq), RbI(aq) and CsI(aq). The spectrum can be divided into two main contributions, both of which are discussed in the text. The dashed line shows the position of the wavenumber 2509 cm–1 where bulk water HDO is located.

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Figure 11

Figure 11. Affected spectrum for NaClO4(aq) and LiClO4(aq). The orange line represents the contribution from the anion (iodide) and the green line the contribution from the alkali metal cation. The dashed line shows the position of the wavenumber 2509 cm–1 where bulk water affected HDO is located. Thin black lines show the Gaussian peaks that are combined to produce the cationic contribution.

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Table 4. Affected Spectra Peaks Are Linear Combinations of Gaussian Peaksa
 center (cm–1)weighted (cm–1)assignment
CsI (N = 7.4)25672567affected spect.
 2568 I–
 2402 noise
RbI (N = 8.9)25652560affected spect.
 2566 I–
 2491 noise
KI (N = 10.6)25592549affected spect.
 2564 I–
 2508 K+/noise
NaI (N = 9.6)25662563affected spect.
 2568 I–
 25422539Na+
 2542 Na+, main
 2374 Na+, assym
NaClO4(N = 11.6)25442559affected spect.
 2633 ClO4–
 25442540Na+
 2544 Na+, main
 2398 Na+, assym
    
LiClO4(N = 10.3)26262536affected spect.
 2630 ClO4–
 2558 Li+
 2564 Li+, second shell
 2490 Li+, first shell
 2449 not explained
a

For NaI, NaClO4 and LiClO4, the cationic contribution is also a linear combination of Gaussian peaks (given in italics).

The iodide peaks in Figure 10 are located at 2564–2568 cm–1, while the perchlorate peaks in Figure 11 are found at 2630–2633 cm–1, both in agreement with literature values. (23)
In order to model the contribution of the hydrated lithium ion, using the perchlorate salt, two peaks are required. The peak at 2490 cm–1 is assigned to the first hydration shell of Li+ while the higher wavenumber peak at 2564 cm–1 is assigned to the second hydration shell. This is in line with the reasoning in Figure 1, that lower wavenumber HDO vibrations correspond to participation in stronger hydrogen bonds. The second hydration shell peak deviates from 2509 cm–1 more than the first hydration shell peak, indicating that second hydration shell molecules participate in hydrogen bonds that are not only weaker than those of the first hydration shell but also weaker than hydrogen bonds in bulk water. This somewhat counterintuitive finding could possibly be explained by an unsatisfactory angle distribution resulting from difficulties of a hydrated lithium to fit into the network of hydrogen bonded bulk water with approximately tetrahedral bond arrangement on average. In Śmiechowski's alkali metal ion investigation (31) an additional peak was found at around 2630 cm–1. As this wavenumber coincides with the peak of the anion in this investigation, it is not possible to observe such a peak in this study. The authors of the previously mentioned work assigned the extra peak to the outermost IR-detectable shell of the cation. If the main peak of the lithium ion does in fact represent the second hydration shell, the interpretation of the peak at 2630 cm–1 peak seems unlikely. It is reasonable to believe that, outside the well-defined first shell, each consecutive hydration sphere should approach the value of bulk water behavior (2509 cm–1). A molecule in a possible third hydration shell should be more similar to bulk water than a molecule in the second hydration shell. The authors of that report consider the alternative interpretation that the main peak represents six-coordinate lithium coexisting with four-coordinate. If this is correct, their interpretation of the discovered 2630 cm–1 band could hold true as the outermost shell would be the same as the second hydration shell. The coexisting coordination number hypothesis that the 2564 cm–1 band would represent six-coordinate lithium does not find any support in this investigation when studying the measured spectra at different concentrations. A possible copresence of four- and six-coordinate hydrated lithium ions should result in a concentration dependent distribution with the six-coordinate hydrate species increasing in relative concentration with increasing dilution. This study shows that there is no such change in the DDIR spectra in the concentration range 0.1 to 1.0 mol·dm–3; Figure S9 in the SI shows the difference spectra in the studies concentration range. This observation supports that the hydrated lithium ion has only one predominating configuration in the studied concentration range, tetrahedral. It shall also be emphasized that no isolated hexaaqualithium ion has been observed in the solid state, Table S1a in the SI. The actual location of the 2564 cm–1 band deviates somewhat from previous investigations (2543 cm–1 and 2530 cm–1 respectively). (15, 31) As the peak separation in this work is smaller than in the previous study, (31) our results may have been affected. The results in ref 15 may have been affected by the use of asymmetric peak contributions and by the suspiciously low N value of 2.0 for the aqueous solution of lithium trifluoroacetate.
In the case of the hydrated sodium ion in perchlorate solution, the main peak is observed at 2544 cm–1, which is in agreement with the result from the previous double difference IR study of alkali metal ions, 2543 cm–1. (31) It was however not possible to model the NaClO4 spectra with only these two bands, but a third one was needed as well. This peak, located at 2398 cm–1, will be regarded as an asymmetry contribution to the cationic peak. It would be unreasonable to take this peak for a first hydration shell, due to its low intensity and its location at much lower wavenumber than the first hydration shell of the lithium ion, which has higher charge density.
While an iodide peak can be found at the expected position, defining the cationic contribution of the iodide solutions presented in Figure 10 is not straightforward. For all ions, and especially for rubidium and cesium, the remaining part of the spectra is very small. As the sodium peak is easily recognized in the aqueous sodium perchlorate solution, Figure 11, it is reasonable to believe that the affected spectra of the sodium iodide solution, Figure 10, would be affected in a similar way. However, the separation of the alkali iodide spectra into two peaks probably does not represent anionic and cationic contribution respectively, as the supposed cationic peak has a much lower intensity than expected. Otherwise it would be tempting to interpret the spectra of the aqueous solutions of rubidium and cesium iodide as having negligible cationic contribution to the water structure. Iodide salts were chosen for the double difference IR experiments as these were the ions used in the LAXS study, but in effect, the peak separation is not sufficiently good to obtain nonoverlapping anionic and cationic peaks with these salts. On the other hand, the solubility of the perchlorate salts of these cations is too low to allow accurate measurements. Modeling the spectra with more Gaussian peaks than necessary for fitting serves no purpose but increases uncertainty markedly. Despite the setbacks of the DDIR alkali iodide experiments, from Figure 10 it can still be seen that the affected spectra of sodium, potassium, rubidium and cesium are quite similar to each other, underlining the similar hydration pattern showed by these ions. One must consider the possibility that a cation contribution with a peak shape and position similar to that of the bulk solvent could be accidentally removed in the previously mentioned water extinction process of finding the affected spectrum. Perhaps this is mostly a semantic problem since hydration shell molecules that behave like bulk water are in fact not affected.
Previous results for potassium show a cation peak location at 2541 cm–1 with a small asymmetry contribution at lower wavelengths. (31) Those results were obtained with the more structure breaking counterion, hexafluorophosphate, PF6–, and allowed for a good peak separation. While going down the group from K+ via Rb+ to Cs+, the affected DDIR spectrum gets narrower, consistent with the decrease in affected number of water molecules, N. To summarize the discussions above, the best lessons to be learned from the double difference IR experiments are not to be found within the differences of spectra, but in the similarities. It seems that the weak hydration behaviors among the larger alkali metal ions are quite similar, and this does not contradict the present knowledge. (6, 44, 65)
The energetical driving force for a salt to refrain from solvation is the lattice energy of the solid phase, as well as the energetical cost of breaking interactions between solvent molecules. Working in the opposite direction is the enthalpy decrease associated with new ionic and molecular interactions between solvent and solute, and between solvent molecules. A solvation reaction, where the latter contribution exceeds the energy requirements for breaking existing bonds in the solid and the solvent, is an exothermic reaction. Endothermic reactions, in which energy released by formation of new bonds falls short of the energy required for breaking old bonds, occur spontaneously due to entropy effects. Considering the equation ΔG = ΔH – TΔS it can be seen that for an endothermic reaction (positive ΔH) the entropy change must be positive and of sufficient magnitude. Positive entropy is caused by the breakdown of a lattice but also by a decrease in the aqueous bulk order due to fewer or less well-defined hydrogen bonds. It can also be seen that if the entropy of the system decreases, representing a substantial increase in hydrogen bonding, the dissolution reaction must be sufficiently exothermic in order to occur spontaneously. This would be the case for hydration of efficient structure making ions. For weakly positive entropy changes, the amount of hydrogen bonding could either increase somewhat, in which case the lattice breakdown is responsible for the positive value, or decrease slightly. We would like to illustrate a view on structure making and breaking in Figure 12.

Figure 12

Figure 12. A two-dimensional approximation of the three-dimensional hydrogen bonded network of water: (a) bulk water, (b) around a structure making ion, (c) around a structure breaking ion. The limitations associated with showing a three-dimensional network in two dimensions, such as incomplete bond illustration, have to be accepted. The effects on water structure are exaggerated in the figure.

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Consider Figure 12:
(a)

In bulk water, O–H···O angles are fairly close to 180°.

(b)

The structure maker does remove water molecules from their network, but also has enough charge density to rebuild a new stronger structured network around itself. As this matrix is even more structured than bulk water, O–H···O angles are even closer to 180°. If the effect is strong enough, the ion is considered to have a second hydration shell, or even a third one. Reorientation times tend to be long as a result of the strong electrostatic interactions. One prerequisite for this behavior is that a water molecule in the close vicinity of the ion is more affected by its environment than a water molecule in bulk water. This attraction can be measured by the location of the OD stretching vibration. If located at lower wavenumbers than 2509 cm–1, the OD oscillator is affected more than one in a bulk water HDO molecule. The molecule is affected by the ion and by neighboring water molecules in its close vicinity.

(c)

As with all particles, when the structure breaker interacts with water, the latter molecule is removed from its network. Contrary to the structure maker, the structure breaking ion does not have enough charge density to rebuild a well structured new water network around itself. As the weakly interacting structure breaking ion is competing with the surrounding hydrogen bonded network, retention times tend to be short. This situation will most certainly occur if a water molecule in the close vicinity of an ion is less affected by its environment than a water molecule in the bulk, indicated by an OD stretching vibration >2509 cm–1.

The claim that affected spectra OD-stretching peaks >2509 cm–1 represent hydration shell molecules which are less affected by their environment than HDO molecules in bulk water is not equivalent to saying that the hydration shell interaction is weaker than bulk water interaction. The reason is that a molecule in the bulk may be affected from more directions than a molecule in the close vicinity of an ion. This may be a reason why water molecules in the hydration shell of a sodium ion have longer reorientation times than bulk water molecules (6, 16, 70) even though bands in DDIR spectra of the hydrated sodium ion are located at higher wavenumbers (15, 17, 18, 20, 30, 31, 33, 85) than the one of bulk water (2509 cm–1): They form stronger bonds than water molecules in the bulk but are still less affected due to geometrical limitations preventing them from forming bonds in four directions. This is the case in predominantly tetrahedral bulk water. A second hydration shell can only form with hydrated ions where the first hydration sphere is affected more by its environment than equivalent molecules in bulk water. Molecules in the first hydration shell of such an ion can affect bulk water molecules sufficiently to perturb the surrounding aqueous hydrogen bond network. Hydrated species with an affected peak above 2509 cm–1 cannot unanimously be claimed to have weaker interactions with water than bulk water interacting with itself. However, all hydrated species with an affected spectrum below 2509 cm–1 should interact with water more strongly than does water in the bulk, based on the following reasoning: an OD-oscillator in the hydration shell cannot have more bonding directions than the four found in an OD-oscillator in the bulk, two acceptors, one donor and the covalent bond to the H in the HDO molecule, and hence, any increased influence from the environment must be due to stronger interactions with the solute. A species such as the sodium ion may be a structure breaker even though it interacts more strongly with water than bulk water molecules interact internally. However any ion which is more affected by its environment, i.e., has an affected peak <2509 cm–1, must be a structure maker. All such ions should have hydration shell reorientation times longer than those of bulk water molecules. It is convenient to define the borderline between structure makers and breakers for an affected spectrum peak at 2509 cm–1, as this is a measure where the entire environmental impact is considered. The alternative definition based on the strength of the interactions with the solute normally coincides with a few exceptions, such as the sodium ion. Reorientation times are not proportional to interaction strength for highly hydrated species with several hydration shells, but should approximately be so for species where hydration occurs by weak electrostatic bonds. All discussion about structure making and breaking ions assumes sufficiently dilute solutions for bulk water to exist in reasonable amount, and is not applicable for solutions where extensive ion-pair formation exists. The effect from an ion on the solution structure could be divided into two contributions: one always occurring structure breaking action induced by the mere presence of a non-neutral particle close to the network, and one structure making action which in many cases is strong enough to reach beyond the first hydration shell in the direction along hydrogen bond axes.
The heats of hydration have been plotted against the metal–oxygen distance, Figure 13. The heats of hydration are taken from the literature, (11) and the metal oxygen distances are the sum of Shannon radii, (37) and the water oxygen radius when bound to metal ions, (80)/the three-coordinate oxide ion, (37) 1.34 Å, except for the cases where more reliable ionic radii have been derived, see above (Li+Nc 4 and 6, Na+Nc 5 and 6, K+Nc 6 and 7). The experimentally obtained values for aqueous solution are also shown in the plot. The position of the experimentally determined metal–oxygen distance can be compared with the positions of the linear regression lines for considered coordination numbers, and thereby the actual coordination number Nc can be estimated, Figure 13. It is assumed that deviation from linear dependence can be neglected. An alternative way to find the hydration number is to compare reliable crystal structure data directly with experimentally obtained values, Figures 4–6 and S2–S4 in the SI.

Figure 13

Figure 13. Heats of hydration as a function of the inverse metal oxygen distance. Dashed trendlines are shown for the occurring hydration numbers 4, 6, 7, 8, 9, 10, and 12. Experimental values from this and a previous (61) work are shown in red-white circles, and a possible linear relationship is shown with a solid line. Other values are based on crystal structures whereof values within blue circles are from the radii proposed in Table 1 and all other values are from Shannon radii of different coordination numbers, ref 37.

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By comparing the regression lines for coordination numbers 6 and 7 in Figure 13, the experimentally obtained Na+–OH2 distance gives a coordination number of 5.7. If the deviating slope of the Nc = 6 trend line is questioned, a similar comparison for Nc = 4 and 7 gives a hydration number of 6.2. The method is judged reliable enough to conclude that the hydration number for the Na+ ion is 6, as trend lines show a fair linear dependence. A direct comparison of the coordination number with crystal structure data, as in Figure 5, supports this conclusion with an indicated coordination number of 6.4. The same methodology for the potassium ion indicates a coordination number of 7.1 from comparing trends of heats of hydration, Figure 13, while directly comparing crystal structures in Figure 6 gives coordination number 6.9. Both methods make use of the available collection of THF solvates as well as the radius of tetrahydrofuran oxygen, 1.32 Å, as described above. As in the case of the sodium ion, the methods are judged reliable for the potassium ion as well and the coordination number 7 is proposed for the solvated K+ ion. The experimental value of Cs+ coincides with the trend line for coordination number 8, Figure 13. Crystal data is poor for the Cs+ ion, but the coordination number 8 is also indicated by Shannon data, Figure S4 in the SI. Hence we propose the coordination number 8 for the Cs+ ion. For Rb+ trends of enthalpy of hydration in Figure 13 suggest Nc = 8.6, but since the rubidium ion is unlikely to have a higher hydration number than the cesium ion, we suggest coordination number 8 for Rb+ as well. The quality of crystal structures is poor, and the hydration number of 7.1 indicated in Figure S3 in the SI can be questioned as it is based on ionic ligands. LAXS studies performed on solutions of lithium iodide and hydroxide did not give any conclusive results and are not reported in this paper. Extrapolation of a possible linear relationship for experimental data indicates a hydration number closer to 4 than 6 for the Li+ ion, and this is in agreement with the large number of four-coordinate crystal structures of lithium. The M–O distance value of 1.90 Å obtained by neutron scattering by Ohtomo and Arakawa (40) indicate four-coordination, Figure 3. Data obtained by X-ray scattering is considered less reliable as X-rays are scattered by electrons and Li+ have very few compared to the solvent. Furthermore, the relative change in radius for the alkali metal ions can be compared, and this is shown in Figure 14. A second degree function serves reasonably well to connect the proposed values for radii in aqueous solution, intersects the determined radius of four coordinated Li+ and extrapolates to approximately zero. We propose a coordination number of 4 for the Li+ ion in aqueous solution.

Figure 14

Figure 14. The relationship between determined ionic radii (diamonds), surface area (triangles) and volume (squares) for the alkali metal ions. Determined values for ionic radii are those proposed in this and previous papers based on experiments in aqueous solution. The radii for six- and four-coordinate Li+ respectively are also shown in open diamonds. Higher degree linear regression functions for volume and area have been forced through the origin while the second degree function for radii is unconstrained.

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Considering Figure 14 again, it can be seen that, even while the ionic radius increase slows down considerably for the heavier alkali metal ions, the changes in volume and surface area are appreciable. Therefore the change in charge density will also be substantial.

Conclusions

A method for classification of atoms in crystal structures depending on their ligands was introduced, see Appendix 3 in the SI. It was found that the average Li–O distance in Li(H2O)4+ was 1.942 Å for 36 observed structures, and this number did not change noticeably if other neutral homo- or heteroleptic monodentate oxygen donor non-ether complexes were allowed. The Li–O distance of Li(H2O)6+ is 2.134 Å as an average for 10 observed structures. The average Na–O distance of Na(H2O)6+ is 2.415 Å as an average of 45 observed structures and does not change much when other neutral homo- or heteroleptic monodentate oxygen donor non-ether complexes are allowed. By subtracting the hydrate oxygen distance of 1.34 Å from the obtained distances, the ionic radii could be determined to 0.60 Å for the four-coordinate lithium ion and to 1.07 Å for the six-coordinate sodium ion. The latter value is well above the one proposed by Shannon. (37) The radius of tetrahydrofuran oxygen in the Li(THF)4+ complex calculated from crystal structures was determined to 1.316 Å, and the same distance in the Na(THF)6+ complex calculated from crystal structures was found to be 1.321 Å. By using the THF oxygen radius, the K–O distance of hypothetical K(H2O)6+ hydrates can be estimated to be 2.72 Å. For the only structure available an analogous calculation for the K(H2O)7+ ion has been estimated to be 2.80 Å. The actual lack of neutral hydrate crystal structures for the heavier alkali metal ions shows the weak H2O binding abilities of K+, Rb+ and Cs+, and it is in line with their loosely formed hydration shells in aqueous solution.
Measurements with LAXS on solutions of alkali metal salts indicate M–O distances of 2.43 Å for Na+, 2.80 Å for K+ and 3.07 Å for Cs+, where the potassium value is an average from aqueous and dimethyl sulfoxide solution. The Rb–O distance has previously been determined to be 2.98 Å. (61)
From double difference IR, it can be seen that the affected spectra of NaClO4 and LiClO4 indicate a second hydration sphere for Li+ but not for Na+. It can be concluded that the hydration behavior for the heavier alkali metals is similar and there are indications that the heavier alkali ions affect surrounding water molecules too little to make them spectroscopically distinguishable. The moderately low charge density of the ions can explain their modest effect on surrounding water.

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  • Corresponding Author
    • Ingmar Persson - Department of Chemistry, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden;  Email: [email protected]
  • Author
    • Johan Mähler - Department of Chemistry, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden

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The financial support from the Swedish Research Council is gratefully acknowledged.

References

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This article references 85 other publications.

  1. 1
    Restrepo-Angulo, I.; De Vizcaya-Ruiz, A.; Camacho, J. J. Appl. Toxicol. 2010, 30, 497– 512
    Google Scholar
    1
    Ion channels in toxicology
    Restrepo-Angulo, Ivan; De Vizcaya-Ruiz, Andrea; Camacho, Javier
    Journal of Applied Toxicology (2010), 30 (6), 497-512CODEN: JJATDK; ISSN:0260-437X. (John Wiley & Sons Ltd.)
    A review. Ion channels play essential roles in human physiol. and toxicol. Cardiac contraction, neural transmission, temp. sensing, insulin release, regulation of apoptosis, cellular pH and oxidative stress, as well as detection of active compds. from chilli, are some of the processes in which ion channels have an important role. Regulation of ion channels by several chems. including those found in air, water and soil represents an interesting potential link between environmental pollution and human diseases; for instance, expression of ion channels in response to exposure to carcinogens is being considered as a potential tool for cancer diagnosis and therapy. Non-specific binding of several drugs to ion channels is responsible for a huge no. of undesirable side-effects, and testing guidelines for several drugs now require ion channel screening for pharmaceutical safety. Animal toxins targeting human ion channels have serious effects on the population and have also provided a remarkable tool to study the mol. structure and function of ion channels. In this review, we will summarize the participation of ion channels in biol. processes extensively used in toxicol. studies, including cardiac function, apoptosis and cell proliferation. Major findings on the adverse effects of drugs on ion channels as well as the regulation of these proteins by different chems., including some pesticides, are also reviewed. Assocn. of ion channels and toxicol. in several biol. processes strongly suggests these proteins to be excellent candidates to follow the toxic effects of xenobiotics, and as potential early indicators of life-threatening situations including chronic degenerative diseases.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtV2gsbbK&md5=0bb502b77c88afcb9f711f41a946f9a4
  2. 2
    Tarascon, J. M.; Armand, M. Nature 2001, 414, 359– 367
    Google Scholar
    2
    Issues and challenges facing rechargeable lithium batteries
    Tarascon, J.-M.; Armand, M.
    Nature (London, United Kingdom) (2001), 414 (6861), 359-367CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)
    A review of the development of lithium-based rechargeable batteries. Ongoing research strategies are highlighted, and the challenges that remain regarding the synthesis, characterization, electrochem. performance, and safety of these systems are discussed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovFGitrY%253D&md5=944485672a9bdf09f6e6a7a199bf3d43
  3. 3
    Greenwood, N. N.; Earnshaw, A. Chemistry of the Elements, 2nd ed.; Butterworth-Heinemann: Oxford, 1997; pp 781– 782.
    Google Scholar
    There is no corresponding record for this reference.
  4. 4
    Avery, S. J. Chem. Technol. Biotechnol. 1995, 62, 3– 16
    Google Scholar
    4
    Microbial interactions with cesium - implications for biotechnology
    Avery, Simon V.
    Journal of Chemical Technology & Biotechnology (1995), 62 (1), 3-16CODEN: JCTBED; ISSN:0268-2575. (Wiley)
    A review with 112 refs., discussing current methodol. for Cs removal from waste effluents, application of microorganisms to biol. metal removal processes, mechanisms of Cs uptake and toxicity in microorganisms, and application of microorganisms to biol. Cs removal and recovery.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXjtlagtbk%253D&md5=147968b679e920388c5eff3d40fcf617
  5. 5
    Ohtaki, H.; Radnai, T. Chem. Rev. 1993, 93, 1157– 1204
    Google Scholar
    5
    Structure and dynamics of hydrated ions
    Ohtaki, Hitoshi; Radnai, Tamas
    Chemical Reviews (Washington, DC, United States) (1993), 93 (3), 1157-204CODEN: CHREAY; ISSN:0009-2665.
    A review with 416 refs.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXit1SlsLc%253D&md5=645ba66a869f2f3b93bdde614d1a411f
  6. 6
    Marcus, Y. Chem. Rev. 2009, 109, 1346– 1370
    Google Scholar
    There is no corresponding record for this reference.
  7. 7
    Persson, I. Pure Appl. Chem. 2010, 82, 1901– 1917
    Google Scholar
    There is no corresponding record for this reference.
  8. 8
    Johansson, G. Adv. Inorg. Chem. 1992, 39, 159– 232
    Google Scholar
    8
    Structures of complexes in solution derived from x-ray diffraction measurements
    Johansson, Georg
    Advances in Inorganic Chemistry (1992), 39 (), 159-232CODEN: AICHEP; ISSN:0898-8838.
    A review with 230 refs.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXksFOjur0%253D&md5=50107460acba195ab0b58749c745a14b
  9. 9
    Richens, D. T. The Chemistry of Aqua Ions; Wiley: New York, 1997.
    Google Scholar
    There is no corresponding record for this reference.
  10. 10
    Djamali, E.; Cobble, J. W. J. Phys. Chem. B 2009, 113, 5200– 5207
    Google Scholar
    There is no corresponding record for this reference.
  11. 11
    Smith, D. W. J. Chem. Educ. 1977, 54, 540– 542
    Google Scholar
    There is no corresponding record for this reference.
  12. 12
    Gurney, R. W. Ionic Processes In Solution; McGraw-Hill: NewYork, 1953; Chapter 10.
    Google Scholar
    There is no corresponding record for this reference.
  13. 13
    Smith, J. D.; Cappa, C. D.; Wilson, K. R.; Cohen, R. C.; Geissler, P. L.; Saykally, R. J. Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 14171– 14174
    Google Scholar
    There is no corresponding record for this reference.
  14. 14
    Soper, A. K.; Weckstrom, K. Biophys. Chem. 2006, 124, 180– 191
    Google Scholar
    There is no corresponding record for this reference.
  15. 15
    Stangret, J.; Gampe, T. J. Phys. Chem. A 2002, 106, 5393– 5402
    Google Scholar
    There is no corresponding record for this reference.
  16. 16
    Rodnikova, M. N. Russ. J. Electrochem. 2003, 39, 192– 197
    Google Scholar
    16
    Negative Hydration of Ions
    Rodnikova, M. N.
    Russian Journal of Electrochemistry (Translation of Elektrokhimiya) (2003), 39 (2), 192-197CODEN: RJELE3; ISSN:1023-1935. (MAIK Nauka/Interperiodica Publishing)
    The neg. hydration, that is the increase in the mobility of water mols. near sufficiently large single-charged ions, is studied by modeling, cold-neutron scattering, and computer modeling. Special attention is paid to the mechanism of neg. hydration and the boundary of transition from pos. to neg. and from neg. to hydrophobic hydration. Hypothetical ions with radii of approx. 1.1 and 3.3 Å correspond to these boundaries. Dynamic characteristics of hydration water in these ions are identical to those of water mols. in bulk water.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhtFSntbw%253D&md5=51c3cd958e18c4f97f5632c1d0dc7c47
  17. 17
    Eriksson, A.; Kristiansson, O.; Lindgren, J. J. Mol. Struct. 1984, 114, 455– 458
    Google Scholar
    There is no corresponding record for this reference.
  18. 18
    Kristiansson, O.; Eriksson, A.; Lindgren, J. Acta Chem. Scand., Ser. A 1984, 38, 613– 618
    Google Scholar
    There is no corresponding record for this reference.
  19. 19
    Kristiansson, O.; Lindgren, J.; Devillepin, J. J. Phys. Chem. 1988, 92, 2680– 2685
    Google Scholar
    There is no corresponding record for this reference.
  20. 20
    Kristinansson, O.; Lindgren, J. J. Mol. Struct. 1988, 177, 537– 541
    Google Scholar
    There is no corresponding record for this reference.
  21. 21
    Kristiansson, O.; Lindgren, J. J. Phys. Chem. 1991, 95, 1488– 1493
    Google Scholar
    There is no corresponding record for this reference.
  22. 22
    Bergström, P.; Lindgren, J.; Kristiansson, O. J. Mol. Liq. 1991, 50, 197– 205
    Google Scholar
    There is no corresponding record for this reference.
  23. 23
    Bergström, P.; Lindgren, J.; Kristiansson, O. J. Phys. Chem. 1991, 95, 8575– 8580
    Google Scholar
    There is no corresponding record for this reference.
  24. 24
    Bergström, P.; Lindgren, J.; Sandström, M.; Zhou, Y. Inorg. Chem. 1992, 31, 150– 152
    Google Scholar
    There is no corresponding record for this reference.
  25. 25
    Lindgren, J.; Bergström J. Phys. Chem. 1991, 95, 7650– 7655
    Google Scholar
    There is no corresponding record for this reference.
  26. 26
    Bergström, P.; Lindgren, J. Inorg. Chem. 1992, 31, 1529– 1533
    Google Scholar
    There is no corresponding record for this reference.
  27. 27
    Stangret, J. Spectrosc. Lett. 1988, 21, 369– 381
    Google Scholar
    27
    Solute-affected vibrational spectra of water in calcium perchlorate aqueous solutions
    Stangret, Janusz
    Spectroscopy Letters (1988), 21 (5), 369-81CODEN: SPLEBX; ISSN:0038-7010.
    A method of investigating hydration of a solute (beginning with infinite diln.) with the use of vibrational spectra is presented. The procedure was applied to aq. Ca(ClO4)2 soln. spectra of OD(HDO) fundamental stretching and combination vibrations of H2O (1100-1300 nm). The no. of Ca(ClO4)2-affected H2O mols. was detd.; the obtained hydration spectra revealed anion- and cation-affected H2O bands.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXlsF2iu7o%253D&md5=fcd5e0d6cfecd8760953282f970dde94
  28. 28
    Stangret, J.; Kostrowicki, J. J. Solution Chem. 1988, 17, 165– 173
    Google Scholar
    There is no corresponding record for this reference.
  29. 29
    Stangret, J.; Gampe, T. J. Phys. Chem. B 1999, 103, 3778– 3783
    Google Scholar
    There is no corresponding record for this reference.
  30. 30
    Stangret, J.; Kamieńska-Piotrowicz, E. J. Chem. Soc., Faraday Trans. 1997, 93, 3463– 3466
    Google Scholar
    There is no corresponding record for this reference.
  31. 31
    Śmiechowski, M.; Gojlo, E.; Stangret, J. J. Phys. Chem. B 2004, 108, 15938– 15943
    Google Scholar
    There is no corresponding record for this reference.
  32. 32
    Śmiechowski, M.; Stangret, J. J. Chem. Phys. 2006, 125, 204508(1)– 204508(14)
    Google Scholar
    There is no corresponding record for this reference.
  33. 33
    Śmiechowski, M.; Stangret, J. J. Phys. Chem. A 2007, 111, 2889– 2897
    Google Scholar
    There is no corresponding record for this reference.
  34. 34
    Śmiechowski, M.; Stangret, J. J. Mol. Struct. 2007, 834–836, 239– 248
    Google Scholar
    There is no corresponding record for this reference.
  35. 35
    Smiechowski, M.; Gojlo, E.; Stangret, J. J. Phys. Chem. B 2009, 113, 7650– 7661
    Google Scholar
    There is no corresponding record for this reference.
  36. 36
    Badger, R. M.; Bauer, S. H. J. Chem. Phys. 1937, 5, 839– 852
    Google Scholar
    There is no corresponding record for this reference.
  37. 37
    Shannon, R. Acta Crystallogr., Sect. A 1976, 32, 751– 767
    Google Scholar
    There is no corresponding record for this reference.
  38. 38
    Inorganic Crystal Structure Database; FIZ Karlsruhe: 2009.
    Google Scholar
    There is no corresponding record for this reference.
  39. 39
    Allen, F. Acta Crystallogr., Sect. B 2002, 58, 380– 388
    Google Scholar
    39
    The Cambridge Structural Database: a quarter of a million crystal structures and rising
    Allen, Frank H.
    Acta Crystallographica, Section B: Structural Science (2002), B58 (3, No. 1), 380-388CODEN: ASBSDK; ISSN:0108-7681. (Blackwell Munksgaard)
    The Cambridge Structural Database (CSD) now contains data for more than a quarter of a million small-mol. crystal structures. The information content of the CSD, together with methods for data acquisition, processing and validation, are summarized, with particular emphasis on the chem. information added by CSD editors. Nearly 80% of new structural data arrives electronically, mostly in CIF format, and the CCDC acts as the official crystal structure data depository for 51 major journals. The CCDC now maintains both a CIF archive (more than 73000 CIFs dating from 1996), as well as the distributed binary CSD archive; the availability of data in both archives is discussed. A statistical survey of the CSD is also presented and projections concerning future accession rates indicate that the CSD will contain at least 500000 crystal structures by the year 2010.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XktVOqu74%253D&md5=406cd0df6ea9035a0ebf8dd9eccbd1f8
  40. 40
    Ohtomo, N.; Arakawa, K. Bull. Chem. Soc. Jpn. 1979, 52, 2755– 2759
    Google Scholar
    There is no corresponding record for this reference.
  41. 41
    Bouazizi, S.; Nasr, S. J. Mol. Struct. 2007, 837, 206– 213
    Google Scholar
    There is no corresponding record for this reference.
  42. 42
    Palinkas, G.; Radnai, T.; Hajdu, F. Z. Naturforsch., A: Phys. Sci 1980, 35, 107– 114
    Google Scholar
    42
    Ion-solvent and solvent-solvent interactions. X-ray study of aqueous alkali chloride solutions
    Palinkas, G.; Radnai, T.; Hajdu, F.
    Zeitschrift fuer Naturforschung, Teil A: Astrophysik, Physik und Physikalische Chemie (1980), 35A (1), 107-14CODEN: ZENAAU; ISSN:0044-3166.
    The 1st neighbor model, FNM, used frequently for the description of hydration is modified by dropping the assumption that the structure of the "free" solvent is identical with that of the pure solvent. The modified model, FNM2, reproduces the exptl. x-ray structure functions of alkali chloride solns. quite well and enables the study of perturbed solvent-solvent interactions. The refined structural parameters reasonably indicate the dependence of the hydration of the alkali cations on their radius and concn. The hydration of Cl- is almost independent of both concn. and the type of counter cation. The model assumes regular symmetry for the 1st neighbor coordination sphere, but the high rms deviations of the water-water distances within the shells of the aggregates indicate considerable individual asymmetries.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3cXhtFOgurc%253D&md5=0a43a3433e773b1b6d963589b6081233
  43. 43
    Smirnov, P. R.; Trostin, V. N. Russ. J. Gen. Chem. 2006, 76, 175– 182
    Google Scholar
    43
    Structure of the nearest surrounding of the Li+ ion in aqueous solutions of its salts
    Smirnov, P. R.; Trostin, V. N.
    Russian Journal of General Chemistry (2006), 76 (2), 175-182CODEN: RJGCEK; ISSN:1070-3632. (Pleiades Publishing, Inc.)
    A concise review (87 refs.). Structural characteristics of hydration of lithium ion in aq. solns. of its salts are studied by X-ray diffraction. The results are summarized and correlated with relevant published data obtained by various methods. The structural parameters of the nearest surrounding of the Li+ ion, such as the coordination no., interparticle distances, and types of ionic assocn., are discussed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjtVKnsb4%253D&md5=e7fa28688acda3ac576dc47d18178a33
  44. 44
    Vinogradov, E. V.; Smirnov, P. R.; Trostin, V. N. Russ. Chem. Bull. 2003, 52, 1253– 1271
    Google Scholar
    44
    Structure of hydrated complexes formed by metal ions of Groups I-III of the Periodic Table in aqueous electrolyte solutions under ambient conditions
    Vinogradov, E. V.; Smirnov, P. R.; Trostin, V. N.
    Russian Chemical Bulletin (Translation of Izvestiya Akademii Nauk, Seriya Khimicheskaya) (2003), 52 (6), 1253-1271CODEN: RCBUEY; ISSN:1066-5285. (Kluwer Academic/Consultants Bureau)
    A review. Published and authors exptl. data on the structures of aq. electrolyte solns. under ambient conditions are considered. The hydrated metal complexes formed in aq. solns. are described systematically depending on the size of the cation, the charge, and the structure of the outer electron shell.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXlslSiurw%253D&md5=85d0b574e13ae3a69b6519b45545372c
  45. 45
    Marcus, Y. Chem. Rev. 1988, 88, 1475– 1498
    Google Scholar
    There is no corresponding record for this reference.
  46. 46
    Loeffler, H.; Rode, B. J. Chem. Phys. 2002, 117, 110– 117
    Google Scholar
    There is no corresponding record for this reference.
  47. 47
    Rudolph, W.; Brooker, M.; Pye, C. J. Phys. Chem. 1995, 99, 3793– 3797
    Google Scholar
    There is no corresponding record for this reference.
  48. 48
    Du, H.; Rasaiah, J. C.; Miller, J. D. J. Phys. Chem. B 2007, 111, 209– 217
    Google Scholar
    There is no corresponding record for this reference.
  49. 49
    Novikov, A. G.; Rodnikova, M. N.; Savostin, V. V.; Sobolev, O. V. J. Mol. Liq. 1999, 82, 83– 104
    Google Scholar
    49
    The study of hydration effects in aqueous solutions of LiCl and CsCl by inelastic neutron scattering
    Novikov, A. G.; Rodnikova, M. N.; Savostin, V. V.; Sobolev, O. V.
    Journal of Molecular Liquids (1999), 82 (1,2), 83-104CODEN: JMLIDT; ISSN:0167-7322. (Elsevier Science S.A.)
    Data anal. of inelastic neutron scattering expts. in 2.14M aq. LiCl and CsCl solns. is presented. The diffusion parameters of hydration water mols. (residence time, diffusion coeffs.) were extd. from the quasi-elastic component of the scattering law S(Q,ω). There are about four mols. in the hydration shell of a Li+ ion, and their diffusion mobility is strongly hampered. A Cs+ ion has about 8 mols. in its hydration shell, and this ion intensifies the diffusion motion of surrounding mols. The dynamic hydration nos. were estd.: 3.7 for a Li+ ion and ∼ 1 for a Cs+ ion. The generalized frequency distributions for water mols. hydrating Li+ and Cs+ ions were obtained from the inelastic part of S(Q,ω). The effects obsd. indicate essential distortion of the hydrogen-bond (H-B) network in the vicinity of both ions, but the character of this distortion has different phys. natures.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmtFejsrg%253D&md5=bc22c2ad08854b598aecf0a867f5c151
  50. 50
    Mancinelli, R.; Botti, A.; Bruni, F.; Ricci, M. A.; Soper, A. K. J.Phys. Chem. B 2007, 111, 13570– 13577
    Google Scholar
    There is no corresponding record for this reference.
  51. 51
    Maeda, M.; Ohtaki, H. Bull. Chem. Soc. Jpn. 1975, 48, 3755– 3756
    Google Scholar
    There is no corresponding record for this reference.
  52. 52
    Ohtomo, N.; Arakawa, K. Bull. Chem. Soc. Jpn. 1980, 53, 1789– 1794
    Google Scholar
    There is no corresponding record for this reference.
  53. 53
    Azam, S. S.; Hofer, T. S.; Randolf, B. R.; Rode, B. M. J. Phys. Chem. A 2009, 113, 1827– 1834
    Google Scholar
    There is no corresponding record for this reference.
  54. 54
    Tongraar, A.; Liedl, K. R.; Rode, B. M. J. Phys. Chem. A 1998, 102, 10340– 10347
    Google Scholar
    There is no corresponding record for this reference.
  55. 55
    Heinje, G.; Luck, W.; Heinzinger, K. J. Phys. Chem. 1987, 91, 331– 338
    Google Scholar
    There is no corresponding record for this reference.
  56. 56
    Bosi, P.; Felici, R.; Rongoni, E.; Sacchetti, F. Nuovo Cimento Soc. Ital. Fis., D 1984, 3, 1029– 1038
    Google Scholar
    56
    On the structure of alkali halide solutions. II. - Neutron and x-ray diffraction
    Bosi, P.; Felici, R.; Rongoni, E.; Sacchetti, F.
    Nuovo Cimento della Societa Italiana di Fisica, D: Condensed Matter, Atomic, Molecular and Chemical Physics, Fluids, Plasmas, Biophysics (1984), 3D (6), 1029-38CODEN: NCSDDN; ISSN:0392-6737.
    The structure factors of NaI solns. in D2O and H2O were detd. by using both neutron and x-ray scattering. The results were analyzed in terms of the structures of the hydration spheres of both Na+ and I- ions. No concn. or temp. dependences of the size of the hydration shells were found; whereas the structure of the free water appeared to be affected, at least at small distances.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXltlOnu7s%253D&md5=bcab336fdb57ba31006c71b72be4131b
  57. 57
    Ohtaki, H.; Fukushima, N. J. Solution Chem. 1992, 21, 23– 38
    Google Scholar
    There is no corresponding record for this reference.
  58. 58
    Chizhik, V. I.; Mikhailov, V. I.; Su, P. C. Theor. Exp. Chem. 1987, 22, 480– 483
    Google Scholar
    There is no corresponding record for this reference.
  59. 59
    Smirnov, P. R.; Trostin, V. N. Russ. J. Gen. Chem. 2007, 77, 2101– 2107
    Google Scholar
    59
    Structures of the nearest surroundings of the K+, Rb+, and Cs+ ions in aqueous solutions of their salts
    Smirnov, P. R.; Trostin, V. N.
    Russian Journal of General Chemistry (2007), 77 (12), 2101-2107CODEN: RJGCEK; ISSN:1070-3632. (Pleiades Publishing, Ltd.)
    A review is presented considering the published data on structural characteristics of hydration of K+, Rb+, and Cs+ ions in aq. solns. of their salts under std. conditions. The structural parameters of the nearest surrounding of the K+, Rb+, and Cs+ ions, such as the coordination nos., interparticle distances, and types of ionic assocn., are discussed. It is noted that, because of weak tendency of these cations to hydration, the parameters of their coordination spheres strongly depend on the concn. and chem. nature of counterions.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsFantbo%253D&md5=6ba79dc79f373f102e0b774cbf8f50c0
  60. 60
    Nikologorskaya, E. L.; Kuznetsov, V. V.; Grechin, O. V.; Trostin, V. N. Russ. J. Inorg. Chem. 2000, 45, 1759– 1766
    Google Scholar
    There is no corresponding record for this reference.
  61. 61
    D’Angelo, P.; Persson, I. Inorg. Chem. 2004, 43, 3543– 3549
    Google Scholar
    There is no corresponding record for this reference.
  62. 62
    Ohkubo, T.; Konishi, T.; Hattori, Y.; Kanoh, H.; Fujikawa, T.; Kaneko, K. J. Am. Chem. Soc. 2002, 124, 11860– 11861
    Google Scholar
    There is no corresponding record for this reference.
  63. 63
    Kubozono, Y.; Hirano, A.; Maeda, H.; Kashino, S.; Emura, S.; Ishida, H. Z. Naturforsch., Teil A 1994, 49, 727– 729
    Google Scholar
    63
    An EXAFS investigation of local structure around Rb+ in aqueous solution
    Kubozono, Yoshihiro; Hirano, Akiko; Maeda, Hironobu; Kashino, Setsuo; Emura, Shuichi; Ishida, Hiroyuki
    Zeitschrift fuer Naturforschung, A: Physical Sciences (1994), 49 (6), 727-9CODEN: ZNASEI; ISSN:0932-0784.
    The Rb+ is surrounded by ca. six O atoms of H2O mols. with Rb-O distance 2.90 (3) Å. The coordination no. and Rb-O distance compare well with those for alk.-metal ions estd. by x-ray diffraction.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXkvFamtL4%253D&md5=0675858b60155b558694b4220695536a
  64. 64
    Ramos, S.; Barnes, A. C.; Neilson, G. W.; Capitan, M. J. Chem. Phys. 2000, 258, 171– 180
    Google Scholar
    There is no corresponding record for this reference.
  65. 65
    San-Román, M. L.; Hernández-Cobos, J.; Saint-Martin, H.; Ortega-Blake, I. Theor. Chem. Acc. 2009, 126, 197– 211
    Google Scholar
    There is no corresponding record for this reference.
  66. 66
    Hofer, T. S.; Randolf, B. R.; Rode, B. M. J. Comput. Chem. 2005, 26, 949– 956
    Google Scholar
    There is no corresponding record for this reference.
  67. 67
    Tamura, Y.; Yamaguchi, T.; Okada, I.; Ohtaki, H. Z. Naturforsch., Teil A 1987, 42, 367– 376
    Google Scholar
    67
    An x-ray diffraction study on the structure of concentrated aqueous caesium iodide and lithium iodide solutions
    Tamura, Yusuke; Yamaguchi, Toshio; Okada, Isao; Ohtaki, Hitoshi
    Zeitschrift fuer Naturforschung, A: Physical Sciences (1987), 42 (4), 367-76CODEN: ZNASEI; ISSN:0932-0784.
    The hydration structures of 2.78 and 5.56 mol CsI and 2.78 and 6.05 mol LiI solns. were studied by x-ray scattering at 293 and 343 K. Differences in the radial distribution functions (DRDFs) were obsd. between the CsI and LiI solns. of similar compns. The DRDFs showed a peak arising from Cs-I contact-ion-pairs at 390 pm for all CsI solns. The effects of the concn. and the temp. on the formation of ion-pairs and on the hydration structure of the ions are discussed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2sXkt1ylurc%253D&md5=f41a6b9fc7867a09ab8e201f11b2a913
  68. 68
    Schwenk, C. F.; Hofer, T. S.; Rode, B. M. J. Phys. Chem. A 2004, 108, 1509– 1514
    Google Scholar
    There is no corresponding record for this reference.
  69. 69
    Mile, V.; Pusztai, L.; Dominguez, H.; Pizio, O. J. Phys. Chem. B 2009, 113, 10760– 10769
    Google Scholar
    There is no corresponding record for this reference.
  70. 70
    Smirnov, P.; Trostin, V. Russ. J. Gen. Chem. 2007, 77, 844– 850
    Google Scholar
    70
    Structure of the nearest surrounding of the Na+ ion in aqueous solutions of its salts
    Smirnov, P. R.; Trostin, V. N.
    Russian Journal of General Chemistry (2007), 77 (5), 844-850CODEN: RJGCEK; ISSN:1070-3632. (Pleiades Publishing, Ltd.)
    Published data obtained by various research methods on structural characteristics of sodium ion hydration in aq. solns. of its salts and authors, x-ray diffraction data were generalized. Structural parameters of the nearest surrounding of Na+ ion, such as its coordination no., interparticle distances, and types of ion assocn., were discussed. The coordination no. of the cation changes from 4 to 6 upon diln. of the solns.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntFyisrg%253D&md5=c569711ce10deab00ac9f85043e85da2
  71. 71
    Helm, L.; Merbach, A. E. Coord. Chem. Rev. 1999, 187, 151– 181
    Google Scholar
    There is no corresponding record for this reference.
  72. 72
    Persson, I.; Sandström, M.; Yokoyama, H.; Chaudhry, M. Z. Naturforsch., Teil A 1995, 50, 21– 37
    Google Scholar
    72
    Structure of the solvated strontium and barium ions in aqueous, dimethyl sulfoxide and pyridine solution, and crystal structure of strontium and barium hydroxide octahydrate
    Persson, Ingmar; Sandstroem, Magnus; Yokoyama, Haruhiko; Chaudhry, Monika
    Zeitschrift fuer Naturforschung, A: Physical Sciences (1995), 50 (1), 21-37CODEN: ZNASEI; ISSN:0932-0784. (Verlag der Zeitschrift fuer Naturforschung)
    Single crystal x-ray data, collected at 298 K, are used to re-det. the crystal structure of the non-isomorphic compds. [Sr(H2O)8](OH)2 and [Ba(H2O)8](OH)2. The eight water oxygen atoms form distorted Archimedean anti-prisms around the octahydrated metal ions with mean metal ion-oxygen distances 2.62 and 2.79 Å for strontium and barium, resp. A second coordination shell of 24 hydrogen-bonded oxygen atoms with mean metal ion-oxygen distances M...OII 4.76 and 4.80 Å, resp., is obsd. The hydroxide ions in both structures have an unusual hydrogen bond arrangement with 5 bonds accepted and one donated. The structure of the solvated strontium and barium ions in aq., DMSO and pyridine solns. has been studied by means of large angle x-ray scattering and extended X-ray absorption fine structure spectroscopy techniques. In aq. soln. independent detns. of the first-sphere metal-oxygen coordination by the two techniques resulted in the bond lengths Sr-O 2.63(2) and Ba-O 2.81(3) Å, and for both metal ions a hydration no. of 8.1(3). The second coordination spheres are very diffuse with only about 13 water mols. at similar M...OII distances as in the crystal structures and 2-3 water mols. closer to the metal ions. In DMSO soln. both ions were found to coordinate 6.0(5) solvent mols. with the distances Sr-O 2.54(1), Sr...S 3.77(1) Å, and Ba-O 2.76(1), Ba...S 3.99 (1) Å. For the solvated ions in pyridine soln. EXAFS measurements yielded the distances Sr-N 2.57(2) and Ba-N 2.78(3) Å, with a probable solvation no. of 6. Correlations of hydration enthalpies and partial molar volumes with exptl. M-O bond distances in aq. soln. are used to discuss hydration nos. and bond character for all of the alk. earth metal ions.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXjvVyqtLc%253D&md5=3edb58bc4a184f100000600fc4722b41
  73. 73
    Calligaris, M. Coord. Chem. Rev. 2004, 248, 351– 375
    Google Scholar
    There is no corresponding record for this reference.
  74. 74
    Stålhandske, C. M. V.; Persson, I.; Sandström, M.; Kamienska-Piotrowicz, E. Inorg. Chem. 1997, 36, 3174– 3182
    Google Scholar
    There is no corresponding record for this reference.
  75. 75
    Johansson, G.; Sandström, M. Chem. Scr. 1973, 4, 195– 198
    Google Scholar
    75
    Computer programs for the analysis of data on x-ray diffraction by liquids
    Johansson, Georg; Sandstrom, Magnus
    Chemica Scripta (1973), 4 (5), 195-8CODEN: CSRPB9; ISSN:0004-2056.
    A short description is given of a set of computer programs, KURVLR and PUTSLR, which can be used for the treatment and anal. of data on x-ray scattering by liqs. and amorphous substances. The programs are extended versions, written in FORTRAN IV. By the KURVLR program, obsd. intensity data can be converted to radial distribution functions, and theor. intensities and peak shapes can be calcd. for assumed mol. models. By PUTSLR a refinement of parameters in the model can be carried out by means of a least squares procedure in which exptl. and theor. calcd. intensities are compared.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2cXmsVKgsQ%253D%253D&md5=495bed1fbcd660c6e650a37ee9871975
  76. 76
    Cromer, D. J. Chem. Phys. 1969, 50, 4857– 4859
    Google Scholar
    There is no corresponding record for this reference.
  77. 77
    Cromer, D.; Mann, J. J. Chem. Phys. 1967, 47, 1892– 1893
    Google Scholar
    There is no corresponding record for this reference.
  78. 78
    Molund, M.; Persson, I. Chem. Scr. 1985, 25, 197– 197
    Google Scholar
    78
    STEPLR - a program for refinements of data on x-ray scattering by liquids
    Molund, Mary; Persson, Ingmar
    Chemica Scripta (1985), 25 (2), 197CODEN: CSRPB9; ISSN:0004-2056.
    The STEPLR program for least-squares refinements of data on x-ray scattering by liqs. simplifies interactive runs at a computer terminal and requires considerably less input data than the previous program. A new subroutine, SCATF, which contains scattering factors, values for the real and the imaginary part of the anomalous dispersion, and incoherent scattering factors for a large no. of neutral atoms, is reported.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2MXls12hsLY%253D&md5=1983481e270866c1f2844865b5bff365
  79. 79
    Levy, H. A.; Danford, M. D.; Narten, A. H. Data Collection and Evaluation with an X-Ray Diffractometer Designed for the Study of Liquid Structure; Oak Ridge National Laboratory: Oak Ridge, TN, 1966.
    Google Scholar
    There is no corresponding record for this reference.
  80. 80
    Beattie, J. K.; Best, S. P.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 1981, 2105– 2111
    Google Scholar
    There is no corresponding record for this reference.
  81. 81
    Andrade-López, N.; Cartas-Rosado, R.; García-Baéz, E.; Contreras, R.; Tlahuext, H. Heteroat. Chem. 1998, 9, 399– 409
    Google Scholar
    81
    Boron heterocycles derived from 2-guanidinobenzimidazole
    Andrade-Lopez, Noemi; Cartas-Rosado, Rocio; Garcia-Baez, Efren; Contreras, Rosalinda; Tlahuext, Hugo
    Heteroatom Chemistry (1998), 9 (4), 399-409CODEN: HETCE8; ISSN:1042-7163. (John Wiley & Sons, Inc.)
    The syntheses and structure detns. of a series of boron heterocycles derived from 2-guanidinobenzimidazole I (R = H, Me) are reported. Structures of new compds., 2-guanidino-1-methyl-benzimidazole (I; R = Me), diphenyl(2-guanidinobenzimidazole-N,N')borates II (R = H, Me, R1 = Ph), (hydroxy)(phenyl)(2-guanidinobenzimidazole-N,N')borates (R = H, Me, R1 = OH), (alkoxy)(phenyl)(2-guanidinobenzimidazole-N,N')borates II (R = H, R1 = MeO, Me2CHO, AcO; R = Me, R1 = MeO), dihydroxy(2-guanidino-1-methyl-benzimidazole-N,N')borate, difluoro(2-guanidinobenzimidazole-N,N')borate, dihydroxy(2-guanidino-1-benzimidazole-N,N')borate potassium salt (III), diphenyl(2-guanidinium-10H-benzimidazole-N,N')borate chloride, (methoxy)(phenyl)(2-guanidinium-10H-benzimidazole-N,N')borate chloride (IV), and N10-borane-(diphenyl-2-guanidinobenzimidazole-N,N')borate, were detd. based on 1H, 13C, 15N, and 11B spectroscopy. The x-ray diffraction structures of II (R = H, Me, R1 = Ph, OH; R = H, R1 = MeO), III, and IV were obtained. The formation of N3-borane adducts derived from I, and the dihydrido-(2-guanidinobenzimidazole-N,N')borate and dihydrido-(2-guanidino-1-methyl-benzimidazole-N,N')borate were obsd. by 11B NMR. The results show that 2-guanidinobenzimidazole gives stable borate heterocycles with a delocalized π electronic system. A dynamic exchange of N-H protons was obsd. with preferred protonation at N-12. The new heterocycles are protonated at N-10 by acidic substances to give pyridinium-type heterocycles or can lose a proton to give iminium salts.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXjs12rtL0%253D&md5=a303e6aeb847b4d8481b5043f7871e89
  82. 82
    Huheey, J. E.; Keiter, E. A.; Keiter, R. L. I. Inorganic Chemistry: Principles of Structure and Reactivity, 4th ed.; Prentice Hall: 1997; pp 122– 127.
    Google Scholar
    There is no corresponding record for this reference.
  83. 83
    Lundberg, D.; Persson, I.; Eriksson, L.; D’Angelo, P.; De Panfilis, S. Inorg. Chem. 2010, 49, 4420– 4432
    Google Scholar
    There is no corresponding record for this reference.
  84. 84
    Becker, M.; Förster, C.; Franzen, C.; Hartrath, J.; Kirsten, E.; Knuth, J.; Klinkhammer, K. W.; Sharma, A.; Hinderberger, D. Inorg. Chem. 2008, 47, 9965– 9978
    Google Scholar
    84
    Persistent Radicals of Trivalent Tin and Lead
    Becker, Marco; Foerster, Christoph; Franzen, Christian; Hartrath, Johannes; Kirsten, Enzio; Knuth, Jorn; Klinkhammer, Karl W.; Sharma, Ajay; Hinderberger, Dariush
    Inorganic Chemistry (2008), 47 (21), 9965-9978CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)
    The authors present synthetic, crystallog., and new EPR spectroscopic work that shows that the synthetic route leading to the recently reported, 1st persistent plumbyl radical •PbEbt3 (Ebt = ethylbis(trimethylsilyl)silyl), i.e., the oxidn. of the related PbEbt3-anion, was easily extended to the synthesis of other persistent mol. mononuclear radicals of Pb and Sn. At 1st, various novel solvates of homoleptic K metalates KSnHyp3 (4a), KPbHyp3 (3a), KSnEbt3 (4b), KPbIbt3 (3c), and KSnIbt3 (4c) (Hyp = tris(trimethylsilyl)silyl, Ibt = isopropylbis(trimethylsilyl)silyl), as well as some heteroleptic metalates, such as [Li(OEt2)2][SnBuHyp2] (3d), [Li(OEt2)2][PbBuHyp2] (4d), [Li(THF)4][PbPhHyp2] (3e), and [K(THF)7][PbHyp2{N(SiMe3)2}] (3f), were synthesized and crystallog. characterized. Through oxidn. by Sn(II) and Pb(II) bis(trimethylsilyl)amides or the related 2,6-di-tert-butylphenoxides, they were oxidized to yield in most cases the corresponding radicals. Five novel persistent homoleptically substituted radicals, i.e., •SnHyp3 (2a), •PbHyp3 (1a), •SnEbt3 (2b), •SnIbt3 (2c), and •PbIbt3 (1c), were characterized by EPR spectroscopy. The stannyl radicals 2a and 2c as well as the plumbyl radical 1c were isolated as intensely colored cryst. compds. and were characterized by x-ray diffraction. Persistent heteroleptically substituted radicals such as •PbHyp2Ph (1e) or •PbHyp2Et (1g) were also generated, and some selected EPR data are given for comparison. The plumbyl radicals •PbR3 exhibit a clean monomol. decay leading to the release of a temp.-dependent stationary concn. of branched silyl radicals. They may thus serve as tunable sources of these reactive species that may be used as reagents for mild radical silylations and/or as initiators for radical polymns. The authors present EPR-spectroscopic studies for the new Sn- and Pb-contg. compds. giving detailed insights into their electronic and geometric structure in soln., as well as structural studies on the cryst. state of the radicals, some of their anionic precursors, and some side-products.
    >> More from SciFinder ®
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  85. 85
    Lindgren, J.; Kristiansson, O.; Paluszkiewicz, C. In Interactions of Water in Ionic and Non-ionic Hydrates; Springer-Verlag: Berlin Heidelberg, 1987; pp 43– 46.
    Google Scholar
    There is no corresponding record for this reference.

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  24. Amy J. Cairns, Katherine L. Hull, Stacey M. Althaus. Specific-Ion Effects Unveil a Route for Modulating Oxidatively Triggered Acid Systems for Reservoir Applications. Inorganic Chemistry 2022, 61 (20) , 7720-7728. https://doi.org/10.1021/acs.inorgchem.1c03804
  25. Murielle F. Delley, Eva M. Nichols, James M. Mayer. Electrolyte Cation Effects on Interfacial Acidity and Electric Fields. The Journal of Physical Chemistry C 2022, 126 (19) , 8477-8488. https://doi.org/10.1021/acs.jpcc.2c01134
  26. Sayoni Mitra, Thien Khuu, Tae Hoon Choi, Rachel M. Huchmala, Kenneth D. Jordan, Anne B. McCoy, Mark A. Johnson. Vibrational Signatures of HNO3 Acidity When Complexed with Microhydrated Alkali Metal Ions, M+·(HNO3)(H2O)n=5 (M = Li, K, Na, Rb, Cs), at 20 K. The Journal of Physical Chemistry A 2022, 126 (10) , 1640-1647. https://doi.org/10.1021/acs.jpca.1c10352
  27. L. M. Anovitz, P. Huestis, N. Rampal, A. G. Stack, J. A. LaVerne, X. Zhang, G. K. Schenter, J. Chun, B. A. Legg, L. Liu, M. Bleuel, C. Gagnon, D. F. R. Mildner. Frustrated Coulombic and Cation Size Effects on Nanoscale Boehmite Aggregation: A Tumbler Small- and Ultra-Small-Angle Neutron Scattering Study. The Journal of Physical Chemistry C 2022, 126 (9) , 4391-4414. https://doi.org/10.1021/acs.jpcc.1c10580
  28. Klaus Lunkenheimer, Dietrich Prescher, Katrina Geggel. Role of Counterions in the Adsorption and Micellization Behavior of 1:1 Ionic Surfactants at Fluid Interfaces─Demonstrated by the Standard Amphiphile System of Alkali Perfluoro-n-octanoates. Langmuir 2022, 38 (3) , 891-902. https://doi.org/10.1021/acs.langmuir.1c00527
  29. Hicham Jabraoui, Stéphane Gin, Thibault Charpentier, Rodolphe Pollet, Jean-Marc Delaye. Leaching and Reactivity at the Sodium Aluminosilicate Glass–Water Interface: Insights from a ReaxFF Molecular Dynamics Study. The Journal of Physical Chemistry C 2021, 125 (49) , 27170-27184. https://doi.org/10.1021/acs.jpcc.1c07266
  30. Andraž Mavrič, Chunhua Cui. Advances and Challenges in Industrial-Scale Water Oxidation on Layered Double Hydroxides. ACS Applied Energy Materials 2021, 4 (11) , 12032-12055. https://doi.org/10.1021/acsaem.1c02604
  31. Sujeong Park, Kideok D. Kwon. Atomistic Insights into the Interlayer Cation and Water Structures of Na-, K-, and Cs-Birnessite. ACS Earth and Space Chemistry 2021, 5 (11) , 3159-3169. https://doi.org/10.1021/acsearthspacechem.1c00259
  32. Huan Shan, Linwei Zhou, Wei Ji, Aidi Zhao. Flexible Alkali–Halogen Bonding in Two Dimensional Alkali-Metal Organic Frameworks. The Journal of Physical Chemistry Letters 2021, 12 (44) , 10808-10814. https://doi.org/10.1021/acs.jpclett.1c03069
  33. Ximeng Wang, Shubham Pandey, Michele Fullarton, Simon R. Phillpot. Study of Incorporating Cesium into Copper Hexacyanoferrate by Density Functional Theory Calculations. The Journal of Physical Chemistry C 2021, 125 (43) , 24273-24283. https://doi.org/10.1021/acs.jpcc.1c08702
  34. Satoshi Yasuda, Kazuhisa Tamura, Masaru Kato, Hidehito Asaoka, Ichizo Yagi. Electrochemically Driven Specific Alkaline Metal Cation Adsorption on a Graphene Interface. The Journal of Physical Chemistry C 2021, 125 (40) , 22154-22162. https://doi.org/10.1021/acs.jpcc.1c03322
  35. Hong Liu, Jian Liu, Bo Yang. Promotional Role of a Cation Intermediate Complex in C2 Formation from Electrochemical Reduction of CO2 over Cu. ACS Catalysis 2021, 11 (19) , 12336-12343. https://doi.org/10.1021/acscatal.1c01072
  36. Constance M. Harris, Bernd Krock, Urban Tillmann, Craig J. Tainter, Donald F. Stec, Aaron J. C. Andersen, Thomas O. Larsen, Kimberly S. Reece, Thomas M. Harris. Alkali Metal- and Acid-Catalyzed Interconversion of Goniodomin A with Congeners B and C. Journal of Natural Products 2021, 84 (9) , 2554-2567. https://doi.org/10.1021/acs.jnatprod.1c00586
  37. Mateusz A. Domański, Karol Kraszewski, Piotr Paluch, Piotr A. Guńka. Arsenic(III)-oxide Intercalates with Potassium Chloride: Water-Induced Varieties and New Synthesis Methods. Crystal Growth & Design 2021, 21 (9) , 5215-5222. https://doi.org/10.1021/acs.cgd.1c00555
  38. Jacob G. Reynolds, Michael D. Britton, Jeremy D. Belsher. A Review of Sodium Nitrite Solubility in Water and Physical Properties of the Saturated Solutions. Journal of Chemical & Engineering Data 2021, 66 (8) , 2931-2941. https://doi.org/10.1021/acs.jced.1c00175
  39. Juhong Park, Sanket Bhoyate, Young-Hoon Kim, Young-Min Kim, Young Hee Lee, Patrick Conlin, Kyeongjae Cho, Wonbong Choi. Unusually High Ion Conductivity in Large-Scale Patternable Two-Dimensional MoS2 Film. ACS Nano 2021, 15 (7) , 12267-12275. https://doi.org/10.1021/acsnano.1c04054
  40. Megan N. Aardema, Jamison Koeman, Douglas A. Vander Griend. Calculating Soft-Sphere Ionic Radii for Solid-State Arrangements from Solution Measurements. Journal of Chemical Education 2021, 98 (7) , 2256-2261. https://doi.org/10.1021/acs.jchemed.0c01506
  41. Linhai Jiang, Chunhua Tony Hu, Francesco De Riccardis, Kent Kirshenbaum. Elaborate Supramolecular Architectures Formed by Co-Assembly of Metal Species and Peptoid Macrocycles. Crystal Growth & Design 2021, 21 (7) , 3889-3901. https://doi.org/10.1021/acs.cgd.1c00209
  42. Annaleise R. Klein, Eirini Sarri, Sabrina E. Kelch, Jade J. Basinski, Shreya Vaidya, Ludmilla Aristilde. Probing the Fate of Different Structures of Beta-Lactam Antibiotics: Hydrolysis, Mineral Capture, and Influence of Organic Matter. ACS Earth and Space Chemistry 2021, 5 (6) , 1511-1524. https://doi.org/10.1021/acsearthspacechem.1c00064
  43. Naresh C. Osti, Bishnu Prasad Thapaliya, Sheng Dai, Madhusudan Tyagi, Eugene Mamontov. Strong Enhancement of Nanoconfined Water Mobility by a Structure Breaking Salt. The Journal of Physical Chemistry Letters 2021, 12 (16) , 4038-4044. https://doi.org/10.1021/acs.jpclett.1c00461
  44. Reshma R. Rao, Botao Huang, Yu Katayama, Jonathan Hwang, Tomoya Kawaguchi, Jaclyn R. Lunger, Jiayu Peng, Yirui Zhang, Asuka Morinaga, Hua Zhou, Hoydoo You, Yang Shao-Horn. pH- and Cation-Dependent Water Oxidation on Rutile RuO2(110). The Journal of Physical Chemistry C 2021, 125 (15) , 8195-8207. https://doi.org/10.1021/acs.jpcc.1c00413
  45. Hicham Jabraoui, Thibault Charpentier, Stéphane Gin, Jean-Marc Delaye, Rodolphe Pollet. Atomic Insights into the Events Governing the Borosilicate Glass–Water Interface. The Journal of Physical Chemistry C 2021, 125 (14) , 7919-7931. https://doi.org/10.1021/acs.jpcc.1c00388
  46. Jun Huang, Shengli Chen, Michael Eikerling. Grand-Canonical Model of Electrochemical Double Layers from a Hybrid Density–Potential Functional. Journal of Chemical Theory and Computation 2021, 17 (4) , 2417-2430. https://doi.org/10.1021/acs.jctc.1c00098
  47. Lanlan Fan, Zhenhuan Li, Weimin Kang. Spontaneous Growth of Alkali Metal Ion-Preintercalated Vanadium Pentoxide for High-Performance Aqueous Zinc-Ion Batteries. ACS Sustainable Chemistry & Engineering 2021, 9 (14) , 5095-5104. https://doi.org/10.1021/acssuschemeng.0c09264
  48. Xinchen Ye, Antonio J. Capezza, Xiong Xiao, Christofer Lendel, Mikael S. Hedenqvist, Vadim G. Kessler, Richard T. Olsson. Protein Nanofibrils and Their Hydrogel Formation with Metal Ions. ACS Nano 2021, 15 (3) , 5341-5354. https://doi.org/10.1021/acsnano.0c10893
  49. Boris S. Zhorov. Possible Mechanism of Ion Selectivity in Eukaryotic Voltage-Gated Sodium Channels. The Journal of Physical Chemistry B 2021, 125 (8) , 2074-2088. https://doi.org/10.1021/acs.jpcb.0c11181
  50. Alejandro Pérez Paz, Angel Rubio. Hydrated Alkali Atoms on Copper(111): A Density Functional Theory Study. The Journal of Physical Chemistry C 2021, 125 (7) , 3868-3879. https://doi.org/10.1021/acs.jpcc.0c10061
  51. Vadim Neklyudov, Viatcheslav Freger. Water and Ion Transfer to Narrow Carbon Nanotubes: Roles of Exterior and Interior. The Journal of Physical Chemistry Letters 2021, 12 (1) , 185-190. https://doi.org/10.1021/acs.jpclett.0c03093
  52. Thomas Ludwig, Joseph A. Gauthier, Colin F. Dickens, Kristopher S. Brown, Stefan Ringe, Karen Chan, Jens K. Nørskov. Atomistic Insight into Cation Effects on Binding Energies in Cu-Catalyzed Carbon Dioxide Reduction. The Journal of Physical Chemistry C 2020, 124 (45) , 24765-24775. https://doi.org/10.1021/acs.jpcc.0c07004
  53. Koji Kimura, Hisao Kiuchi, Kouichi Hayashi, Akiyoshi Nakata, Fumika Fujisaki, Koji Nishio, Toshiharu Fukunaga, Eiichiro Matsubara. Application of Anomalous X-ray Scattering Method to Liquid Electrolytes Used in a Battery: Local Structural Analysis around a Dilute Metallic Ion. Analytical Chemistry 2020, 92 (14) , 9956-9962. https://doi.org/10.1021/acs.analchem.0c01525
  54. Ya-Qing Xiang, Xu Yao, Jin-Hong Lin, Xiao-Jian Ou, Rong Li, Yu-Sheng Zhou, Dong-Hai Yu, Ji-Chang Xiao. Extraction Behavior of Acidic Phosphorus-Containing Compounds to Some Metal Ions: A Combination Research of Experimental and Theoretical Investigations. The Journal of Physical Chemistry A 2020, 124 (24) , 5033-5041. https://doi.org/10.1021/acs.jpca.0c01594
  55. Gianni Klesse, Shanlin Rao, Stephen J. Tucker, Mark S.P. Sansom. Induced Polarization in Molecular Dynamics Simulations of the 5-HT3 Receptor Channel. Journal of the American Chemical Society 2020, 142 (20) , 9415-9427. https://doi.org/10.1021/jacs.0c02394
  56. Alessandro Ferretti, Marco d’Ischia, Giacomo Prampolini. Benchmarking Cation−π Interactions: Assessment of Density Functional Theory and Möller–Plesset Second-Order Perturbation Theory Calculations with Optimized Basis Sets (mp2mod) for Complexes of Benzene, Phenol, and Catechol with Na+, K+, Rb+, and Cs+. The Journal of Physical Chemistry A 2020, 124 (17) , 3445-3459. https://doi.org/10.1021/acs.jpca.0c02090
  57. Takuma Yagasaki, Masakazu Matsumoto, Hideki Tanaka. Lennard-Jones Parameters Determined to Reproduce the Solubility of NaCl and KCl in SPC/E, TIP3P, and TIP4P/2005 Water. Journal of Chemical Theory and Computation 2020, 16 (4) , 2460-2473. https://doi.org/10.1021/acs.jctc.9b00941
  58. Manisha Singh, Cheong See Yin, Samuel J. Page, Yuqing Liu, Gautama Wicaksono, Rajashekhar Pujar, Shyam Kumar Choudhary, Giridhar U. Kulkarni, Jun Chen, John V. Hanna, Richard D. Webster, Terry W. J. Steele. Synergistic Voltaglue Adhesive Mechanisms with Alternating Electric Fields. Chemistry of Materials 2020, 32 (6) , 2440-2449. https://doi.org/10.1021/acs.chemmater.9b04962
  59. Hiroto Tachikawa, Kazuko Haga, Sadayuki Watanabe, Kazuo Yamada. Local Structures and Electronic States of C-S-H–Sodium–H2O Interface: NMR and DFT Studies. The Journal of Physical Chemistry C 2020, 124 (10) , 5672-5680. https://doi.org/10.1021/acs.jpcc.9b11302
  60. Paul Grey, Susete N. Fernandes, Diana Gaspar, Jonas Deuermeier, Rodrigo Martins, Elvira Fortunato, Maria H. Godinho, Luis Pereira. Ionically Modified Cellulose Nanocrystal Self-Assembled Films with a Mesoporous Twisted Superstructure: Polarizability and Application in Ion-Gated Transistors. ACS Applied Electronic Materials 2020, 2 (2) , 426-436. https://doi.org/10.1021/acsaelm.9b00652
  61. Animesh Patra, Subhadip Roy, Subhamoy Saha, Dipak K. Palit, Jahur A. Mondal. Observation of Extremely Weakly Interacting OH (∼3600 cm–1) in the Vicinity of High Charge Density Metal Ions (Mz+; z = 1, 2, 3): A Structural Heterogeneity in the Extended Hydration Shell. The Journal of Physical Chemistry C 2020, 124 (5) , 3028-3036. https://doi.org/10.1021/acs.jpcc.9b09692
  62. Tahereh Mohammadi Hafshejani, Siegfried Hohmann, Alexei Nefedov, Matthias Schwotzer, Gerald Brenner-Weiss, Mohammadreza Izadifar, Peter Thissen. Formation and Stability of Nontoxic Perovskite Precursor. Langmuir 2019, 35 (49) , 16217-16225. https://doi.org/10.1021/acs.langmuir.9b03037
  63. Hao Zeng, Viktor F. Rozsa, Nicole Xike Nie, Zhe Zhang, Tuan Anh Pham, Giulia Galli, Nicolas Dauphas. Ab Initio Calculation of Equilibrium Isotopic Fractionations of Potassium and Rubidium in Minerals and Water. ACS Earth and Space Chemistry 2019, 3 (11) , 2601-2612. https://doi.org/10.1021/acsearthspacechem.9b00180
  64. Yu Peng, Anthony E. Hughes, James I. Mardel, Glen B. Deacon, Peter C. Junk, Maria Forsyth, Bruce R. W. Hinton, Anthony E. Somers. Leaching Behavior and Corrosion Inhibition of a Rare Earth Carboxylate Incorporated Epoxy Coating System. ACS Applied Materials & Interfaces 2019, 11 (39) , 36154-36168. https://doi.org/10.1021/acsami.9b13722
  65. Li-Zhen Sun, Yuanzhe Zhou, Shi-Jie Chen. Predicting Monovalent Ion Correlation Effects in Nucleic Acids. ACS Omega 2019, 4 (8) , 13435-13446. https://doi.org/10.1021/acsomega.9b01689
  66. Amaury Coste, Arnaud Poulesquen, Olivier Diat, Jean-François Dufrêche, Magali Duvail. Investigation of the Structure of Concentrated NaOH Aqueous Solutions by Combining Molecular Dynamics and Wide-Angle X-ray Scattering. The Journal of Physical Chemistry B 2019, 123 (24) , 5121-5130. https://doi.org/10.1021/acs.jpcb.9b00495
  67. Haylie L. Lobeck, Jordan K. Isner, Peter C. Burns. Transformation of Uranyl Peroxide Studtite, [(UO2)(O2)(H2O)2](H2O)2, to Soluble Nanoscale Cage Clusters. Inorganic Chemistry 2019, 58 (10) , 6781-6789. https://doi.org/10.1021/acs.inorgchem.9b00230
  68. Meng Tian, Ruihan Li, Chaofeng Liu, Donghui Long, Guozhong Cao. Aqueous Al-Ion Supercapacitor with V2O5 Mesoporous Carbon Electrodes. ACS Applied Materials & Interfaces 2019, 11 (17) , 15573-15580. https://doi.org/10.1021/acsami.9b02030
  69. Irene Weber, Nikki Gerrard, Andrew Hodgson, Karina Morgenstern. Structural Changes to Supported Water Nanoislands Induced by Kosmotropic Ions. The Journal of Physical Chemistry C 2019, 123 (11) , 6861-6868. https://doi.org/10.1021/acs.jpcc.8b12202
  70. Tor Sewring, Weizhen Zhu, Maria Sedin, Hans Theliander. Predictions of Pair Interaction Potentials between Kraft Lignin Macromolecules in Black Liquors by Utilization of a Modified Poisson–Boltzmann Approach. Industrial & Engineering Chemistry Research 2019, 58 (8) , 3427-3439. https://doi.org/10.1021/acs.iecr.8b05929
  71. Debbie Zhuang, Marc Riera, Gregory K. Schenter, John L. Fulton, Francesco Paesani. Many-Body Effects Determine the Local Hydration Structure of Cs+ in Solution. The Journal of Physical Chemistry Letters 2019, 10 (3) , 406-412. https://doi.org/10.1021/acs.jpclett.8b03829
  72. Andreas A. Zavitsas. Quest To Demystify Water: Ideal Solution Behaviors Are Obtained by Adhering to the Equilibrium Mass Action Law. The Journal of Physical Chemistry B 2019, 123 (4) , 869-883. https://doi.org/10.1021/acs.jpcb.8b07166
  73. Chang Lu, Marcus W. Wright, Xiao Ma, Hui Li, Dominique S. Itanze, Jake A. Carter, Corey A. Hewitt, George L. Donati, David L. Carroll, Pamela M. Lundin, Scott M. Geyer. Cesium Oleate Precursor Preparation for Lead Halide Perovskite Nanocrystal Synthesis: The Influence of Excess Oleic Acid on Achieving Solubility, Conversion, and Reproducibility. Chemistry of Materials 2019, 31 (1) , 62-67. https://doi.org/10.1021/acs.chemmater.8b04876
  74. Santanu Roy, Vyacheslav S. Bryantsev. Finding Order in the Disordered Hydration Shell of Rapidly Exchanging Water Molecules around the Heaviest Alkali Cs+ and Fr+. The Journal of Physical Chemistry B 2018, 122 (50) , 12067-12076. https://doi.org/10.1021/acs.jpcb.8b08414
  75. Trent R. Graham, David Semrouni, Eugene Mamontov, Anibal J. Ramirez-Cuesta, Katharine Page, Aurora Clark, Gregory K. Schenter, Carolyn I. Pearce, Andrew G. Stack, Hsiu-Wen Wang. Coupled Multimodal Dynamics of Hydrogen-Containing Ion Networks in Water-Deficient, Sodium Hydroxide-Aluminate Solutions. The Journal of Physical Chemistry B 2018, 122 (50) , 12097-12106. https://doi.org/10.1021/acs.jpcb.8b09375
  76. Niko Prasetyo, Philippe H. Hünenberger, Thomas S. Hofer. Single-Ion Thermodynamics from First Principles: Calculation of the Absolute Hydration Free Energy and Single-Electrode Potential of Aqueous Li+ Using ab Initio Quantum Mechanical/Molecular Mechanical Molecular Dynamics Simulations. Journal of Chemical Theory and Computation 2018, 14 (12) , 6443-6459. https://doi.org/10.1021/acs.jctc.8b00729
  77. Nicolas Dubouis, Alessandra Serva, Elodie Salager, Michael Deschamps, Mathieu Salanne, Alexis Grimaud. The Fate of Water at the Electrochemical Interfaces: Electrochemical Behavior of Free Water Versus Coordinating Water. The Journal of Physical Chemistry Letters 2018, 9 (23) , 6683-6688. https://doi.org/10.1021/acs.jpclett.8b03066
  78. Jacob G. Reynolds. Salt Solubilities in Aqueous Solutions of NaNO3, NaNO2, NaCl, and NaOH: A Hofmeister-like Series for Understanding Alkaline Nuclear Waste. ACS Omega 2018, 3 (11) , 15149-15157. https://doi.org/10.1021/acsomega.8b02052
  79. Rachel Guia P. Giron, Xin Chen, Erika Callagon La Plante, Maxim N. Gussev, Keith J. Leonard, Gaurav Sant. Revealing How Alkali Cations Affect the Surface Reactivity of Stainless Steel in Alkaline Aqueous Environments. ACS Omega 2018, 3 (11) , 14680-14688. https://doi.org/10.1021/acsomega.8b02227
  80. Matti Hellström, Michele Ceriotti, Jörg Behler. Nuclear Quantum Effects in Sodium Hydroxide Solutions from Neural Network Molecular Dynamics Simulations. The Journal of Physical Chemistry B 2018, 122 (44) , 10158-10171. https://doi.org/10.1021/acs.jpcb.8b06433
  81. Shateesh Battu, Mahesh Itagi, Zahid Manzoor Bhat, Siddhi Khaire, Alagar Raja Kottaichamy, Lokesh Koodlur Sannegowda, Ravikumar Thimmappa, Musthafa Ottakam Thotiyl. Metal Coordination Polymer Framework Governed by Heat of Hydration for Noninvasive Differentiation of Alkali Metal Series. Analytical Chemistry 2018, 90 (21) , 12917-12922. https://doi.org/10.1021/acs.analchem.8b03541
  82. Ingmar Persson, Mylène Trublet, Wantana Klysubun. Structure Determination of Phosphoric Acid and Phosphate Ions in Aqueous Solution Using EXAFS Spectroscopy and Large Angle X-ray Scattering. The Journal of Physical Chemistry A 2018, 122 (37) , 7413-7420. https://doi.org/10.1021/acs.jpca.8b05641
  83. Alex Smolyanitsky, Eugene Paulechka, Kenneth Kroenlein. Aqueous Ion Trapping and Transport in Graphene-Embedded 18-Crown-6 Ether Pores. ACS Nano 2018, 12 (7) , 6677-6684. https://doi.org/10.1021/acsnano.8b01692
  84. Marc Riera, Sandra E. Brown, Francesco Paesani. Isomeric Equilibria, Nuclear Quantum Effects, and Vibrational Spectra of M+(H2O)n=1–3 Clusters, with M = Li, Na, K, Rb, and Cs, through Many-Body Representations. The Journal of Physical Chemistry A 2018, 122 (27) , 5811-5821. https://doi.org/10.1021/acs.jpca.8b04106
  85. Jing Xie, Harrison A. Neal, Jennifer Szymanowski, Peter C. Burns, Todd M. Alam, May Nyman, Laura Gagliardi. Resolving Confined 7Li Dynamics of Uranyl Peroxide Capsule U24. Inorganic Chemistry 2018, 57 (9) , 5514-5525. https://doi.org/10.1021/acs.inorgchem.8b00474
  86. Yun Wang, Xu Liu, Junxian Liu, Mohammad Al-Mamun, Alan Wee-Chung Liew, Huajie Yin, William Wen, Yu Lin Zhong, Porun Liu, Huijun Zhao. Electrolyte Effect on Electrocatalytic Hydrogen Evolution Performance of One-Dimensional Cobalt–Dithiolene Metal–Organic Frameworks: A Theoretical Perspective. ACS Applied Energy Materials 2018, 1 (4) , 1688-1694. https://doi.org/10.1021/acsaem.8b00174
  87. Haidy Metwally, Lars Konermann. Crown Ether Effects on the Location of Charge Carriers in Electrospray Droplets: Implications for the Mechanism of Protein Charging and Supercharging. Analytical Chemistry 2018, 90 (6) , 4126-4134. https://doi.org/10.1021/acs.analchem.8b00099
  88. Yihua Liu, Tomoya Kawaguchi, Michael S. Pierce, Vladimir Komanicky, Hoydoo You. Layering and Ordering in Electrochemical Double Layers. The Journal of Physical Chemistry Letters 2018, 9 (6) , 1265-1271. https://doi.org/10.1021/acs.jpclett.8b00123
  89. Shi-Fan Xue, Zi-Han Chen, Xin-Yue Han, Zi-Yang Lin, Qi-Xian Wang, Min Zhang, Guoyue Shi. DNA Encountering Terbium(III): A Smart “Chemical Nose/Tongue” for Large-Scale Time-Gated Luminescent and Lifetime-Based Sensing. Analytical Chemistry 2018, 90 (5) , 3443-3451. https://doi.org/10.1021/acs.analchem.7b05167
  90. Ko Higashitani, Kouta Nakamura, Tomonori Fukasawa, Katsumi Tsuchiya, and Yasushige Mori . Ionic Specificity in Rapid Coagulation of Silica Nanoparticles. Langmuir 2018, 34 (7) , 2505-2510. https://doi.org/10.1021/acs.langmuir.7b04081
  91. Bedika Phukan, Samir Ghorai, Kashmiri Deka, Pritam Deb, and Chandan Mukherjee . Interactions of Alkali and Alkaline-Earth Metals in Water-Soluble Heterometallic FeIII/M (M = Na+, K+, Ca2+)-Type Coordination Complex. Crystal Growth & Design 2018, 18 (1) , 531-539. https://doi.org/10.1021/acs.cgd.7b01588
  92. Kazi Sadman, Qifeng Wang, Yaoyao Chen, Bavand Keshavarz, Zhang Jiang, and Kenneth R. Shull . Influence of Hydrophobicity on Polyelectrolyte Complexation. Macromolecules 2017, 50 (23) , 9417-9426. https://doi.org/10.1021/acs.macromol.7b02031
  93. Masanari Nagasaka, Hayato Yuzawa, and Nobuhiro Kosugi . Interaction between Water and Alkali Metal Ions and Its Temperature Dependence Revealed by Oxygen K-Edge X-ray Absorption Spectroscopy. The Journal of Physical Chemistry B 2017, 121 (48) , 10957-10964. https://doi.org/10.1021/acs.jpcb.7b09789
  94. Emma L. DeWalt-Kerian, Sun Kim, Md. Shafiul Azam, Hongbo Zeng, Qingxia Liu, and Julianne M. Gibbs . pH-Dependent Inversion of Hofmeister Trends in the Water Structure of the Electrical Double Layer. The Journal of Physical Chemistry Letters 2017, 8 (13) , 2855-2861. https://doi.org/10.1021/acs.jpclett.7b01005
  95. Tyler Hawkins, Nicholas Allen, Michael L. Machesky, David J. Wesolowski, and Nadine Kabengi . Ion Exchange Thermodynamics at the Rutile–Water Interface: Flow Microcalorimetric Measurements and Surface Complexation Modeling of Na–K–Rb–Cl–NO3 Adsorption. Langmuir 2017, 33 (20) , 4934-4941. https://doi.org/10.1021/acs.langmuir.7b00867
  96. Hamza Goubaa, Freddy Escobar-Teran, Ibtissam Ressam, Wanli Gao, Abdelkrim El Kadib, Ivan T. Lucas, Mustapha Raihane, Mohammed Lahcini, Hubert Perrot, and Ozlem Sel . Dynamic Resolution of Ion Transfer in Electrochemically Reduced Graphene Oxides Revealed by Electrogravimetric Impedance. The Journal of Physical Chemistry C 2017, 121 (17) , 9370-9380. https://doi.org/10.1021/acs.jpcc.7b01421
  97. Wenzhong Zhang, Risto Koivula, Elmo Wiikinkoski, Junhua Xu, Sami Hietala, Jukka Lehto, and Risto Harjula . Efficient and Selective Recovery of Trace Scandium by Inorganic Titanium Phosphate Ion-Exchangers from Leachates of Waste Bauxite Residue. ACS Sustainable Chemistry & Engineering 2017, 5 (4) , 3103-3114. https://doi.org/10.1021/acssuschemeng.6b02870
  98. Yimeng Yang, Qian Liu, Liang Zhang, Haizhu Yu, and Zhimin Dang . Mechanistic Investigation on Oxygen-Mediated Photoredox Diels–Alder Reactions with Chromium Catalysts. Organometallics 2017, 36 (3) , 687-698. https://doi.org/10.1021/acs.organomet.6b00886
  99. Mark D. Ellison, Samuel Menges, Laura Nebel, Gabrielle D’Arcangelo, Anna Kramer, Lee Drahushuk, Jesse Benck, Steven Shimizu, and Michael S. Strano . Electrokinetic Transport of Methanol and Lithium Ions Through a 2.25-nm-Diameter Carbon Nanotube Nanopore. The Journal of Physical Chemistry C 2017, 121 (3) , 2005-2013. https://doi.org/10.1021/acs.jpcc.6b12104
  100. Andinet Ejigu, Ian A. Kinloch, and Robert A. W. Dryfe . Single Stage Simultaneous Electrochemical Exfoliation and Functionalization of Graphene. ACS Applied Materials & Interfaces 2017, 9 (1) , 710-721. https://doi.org/10.1021/acsami.6b12868
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  • Abstract

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    Figure 1

    Figure 1. (a) HDO in bulk water, νO–D = 2509 cm–1, dO(···D)–O = 2.89 Å. (b) HDO affected by a structure making cation, νO–D < 2509 cm–1, dO(···D)–O < 2.89 Å. (c) HDO affected by a structure breaking cation, νO–D > 2509 cm–1, dO(···D)–O > 2.89 Å. O–D bond strength is indicated by the line thickness, and orange color represent a D atom.

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    Figure 2

    Figure 2. Crystal structures of neutral, homoleptic, Li+ hydrates. The dashed line is drawn between mean values for four- and six-coordination (geometrically approved atoms). Error bars correspond to two standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses.

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    Figure 3

    Figure 3. Crystal structures of neutral, monodentate non-ether Li+ complexes. The dashed line is drawn between mean values for four- and six-coordination (geometrically approved atoms). Error bars correspond to two standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses.

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    Figure 4

    Figure 4. Crystal structures of neutral, homoleptic, Na+ hydrates. The dashed line is drawn between mean values for five- and six-coordination (geometrically approved atoms). Error bars correspond to ±2 standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses. A green circle represents the experimental M–O distance determined by LAXS for six-coordination in this study.

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    Figure 5

    Figure 5. Crystal structures of neutral, non-ether, monodentate Na+ complexes. The dashed line is drawn between mean values for five- and six-coordination (geometrically approved atoms). Error bars correspond to ±2 standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses. A green circle represents the experimental M–O distance determined by LAXS for six-coordination in this study.

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    Figure 6

    Figure 6. Crystal structures of potassium THF solvates. The error bar corresponds to ±2 standard deviations. The sums of the radii given by Shannon and the oxygen radius are shown as orange crosses. The dashed line is drawn 0.02 Å above average values for six- and seven-coordination in order to correct for the smaller size of THF oxygen relative to water oxygen (see text). A green circle represents the experimental M–O distance determined by LAXS for seven-coordination in this study.

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    Figure 7

    Figure 7. (Top) LAXS radial distribution curves for a 2.001 mol·dm–3 aqueous solution of cesium iodide. Upper part: Separate model contributions (offset: 20) of the hydrated cesium ion (black line), the hydrated iodide ion (red line) and the aqueous bulk (blue line). (Middle) Experimental RDF: D(r) – 4πr2ρo (red line), sum of model contributions (black line) and the difference between experimental and calculated functions (blue line). (Bottom) Reduced LAXS intensity functions s·i(s) (solid line); model s·icalc(s) (dashed line).

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    Figure 8

    Figure 8. (Top) LAXS radial distribution curves for a 2.007 mol·dm–3 aqueous solution of potassium iodide. Upper part: Separate model contributions (offset: 12) of the hydrated potassium ion (black line), the hydrated iodide ion (red line) and the aqueous bulk (blue line). (Middle) Experimental RDF: D(r) – 4πr2ρo (red line), sum of model contributions (black line) and the difference between experimental and calculated functions (blue line). (Bottom) Reduced LAXS intensity functions s·i(s) (solid line); model s·icalc(s) (dashed line).

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    Figure 9

    Figure 9. (Top) LAXS radial distribution curves for a 2.007 mol·dm–3 aqueous solution of sodium iodide. Upper part: Separate model contributions (offset: 14) of the hydrated sodium ion (black line), the hydrated iodide ion (red line) and the aqueous bulk (blue line). (Middle) Experimental RDF: D(r) – 4πr2ρo (red line), sum of model contributions (black line) and the difference between experimental and calculated functions (blue line). (Bottom) Reduced LAXS intensity functions s·i(s) (solid line); model s·icalc(s) (dashed line).

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    Figure 10

    Figure 10. Affected spectrum for NaI(aq), KI(aq), RbI(aq) and CsI(aq). The spectrum can be divided into two main contributions, both of which are discussed in the text. The dashed line shows the position of the wavenumber 2509 cm–1 where bulk water HDO is located.

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    Figure 11

    Figure 11. Affected spectrum for NaClO4(aq) and LiClO4(aq). The orange line represents the contribution from the anion (iodide) and the green line the contribution from the alkali metal cation. The dashed line shows the position of the wavenumber 2509 cm–1 where bulk water affected HDO is located. Thin black lines show the Gaussian peaks that are combined to produce the cationic contribution.

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    Figure 12

    Figure 12. A two-dimensional approximation of the three-dimensional hydrogen bonded network of water: (a) bulk water, (b) around a structure making ion, (c) around a structure breaking ion. The limitations associated with showing a three-dimensional network in two dimensions, such as incomplete bond illustration, have to be accepted. The effects on water structure are exaggerated in the figure.

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    Figure 13

    Figure 13. Heats of hydration as a function of the inverse metal oxygen distance. Dashed trendlines are shown for the occurring hydration numbers 4, 6, 7, 8, 9, 10, and 12. Experimental values from this and a previous (61) work are shown in red-white circles, and a possible linear relationship is shown with a solid line. Other values are based on crystal structures whereof values within blue circles are from the radii proposed in Table 1 and all other values are from Shannon radii of different coordination numbers, ref 37.

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    Figure 14

    Figure 14. The relationship between determined ionic radii (diamonds), surface area (triangles) and volume (squares) for the alkali metal ions. Determined values for ionic radii are those proposed in this and previous papers based on experiments in aqueous solution. The radii for six- and four-coordinate Li+ respectively are also shown in open diamonds. Higher degree linear regression functions for volume and area have been forced through the origin while the second degree function for radii is unconstrained.

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    This article references 85 other publications.

    1. 1
      Restrepo-Angulo, I.; De Vizcaya-Ruiz, A.; Camacho, J. J. Appl. Toxicol. 2010, 30, 497– 512
      Google Scholar
      1
      Ion channels in toxicology
      Restrepo-Angulo, Ivan; De Vizcaya-Ruiz, Andrea; Camacho, Javier
      Journal of Applied Toxicology (2010), 30 (6), 497-512CODEN: JJATDK; ISSN:0260-437X. (John Wiley & Sons Ltd.)
      A review. Ion channels play essential roles in human physiol. and toxicol. Cardiac contraction, neural transmission, temp. sensing, insulin release, regulation of apoptosis, cellular pH and oxidative stress, as well as detection of active compds. from chilli, are some of the processes in which ion channels have an important role. Regulation of ion channels by several chems. including those found in air, water and soil represents an interesting potential link between environmental pollution and human diseases; for instance, expression of ion channels in response to exposure to carcinogens is being considered as a potential tool for cancer diagnosis and therapy. Non-specific binding of several drugs to ion channels is responsible for a huge no. of undesirable side-effects, and testing guidelines for several drugs now require ion channel screening for pharmaceutical safety. Animal toxins targeting human ion channels have serious effects on the population and have also provided a remarkable tool to study the mol. structure and function of ion channels. In this review, we will summarize the participation of ion channels in biol. processes extensively used in toxicol. studies, including cardiac function, apoptosis and cell proliferation. Major findings on the adverse effects of drugs on ion channels as well as the regulation of these proteins by different chems., including some pesticides, are also reviewed. Assocn. of ion channels and toxicol. in several biol. processes strongly suggests these proteins to be excellent candidates to follow the toxic effects of xenobiotics, and as potential early indicators of life-threatening situations including chronic degenerative diseases.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtV2gsbbK&md5=0bb502b77c88afcb9f711f41a946f9a4
    2. 2
      Tarascon, J. M.; Armand, M. Nature 2001, 414, 359– 367
      Google Scholar
      2
      Issues and challenges facing rechargeable lithium batteries
      Tarascon, J.-M.; Armand, M.
      Nature (London, United Kingdom) (2001), 414 (6861), 359-367CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)
      A review of the development of lithium-based rechargeable batteries. Ongoing research strategies are highlighted, and the challenges that remain regarding the synthesis, characterization, electrochem. performance, and safety of these systems are discussed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovFGitrY%253D&md5=944485672a9bdf09f6e6a7a199bf3d43
    3. 3
      Greenwood, N. N.; Earnshaw, A. Chemistry of the Elements, 2nd ed.; Butterworth-Heinemann: Oxford, 1997; pp 781– 782.
      Google Scholar
      There is no corresponding record for this reference.
    4. 4
      Avery, S. J. Chem. Technol. Biotechnol. 1995, 62, 3– 16
      Google Scholar
      4
      Microbial interactions with cesium - implications for biotechnology
      Avery, Simon V.
      Journal of Chemical Technology & Biotechnology (1995), 62 (1), 3-16CODEN: JCTBED; ISSN:0268-2575. (Wiley)
      A review with 112 refs., discussing current methodol. for Cs removal from waste effluents, application of microorganisms to biol. metal removal processes, mechanisms of Cs uptake and toxicity in microorganisms, and application of microorganisms to biol. Cs removal and recovery.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXjtlagtbk%253D&md5=147968b679e920388c5eff3d40fcf617
    5. 5
      Ohtaki, H.; Radnai, T. Chem. Rev. 1993, 93, 1157– 1204
      Google Scholar
      5
      Structure and dynamics of hydrated ions
      Ohtaki, Hitoshi; Radnai, Tamas
      Chemical Reviews (Washington, DC, United States) (1993), 93 (3), 1157-204CODEN: CHREAY; ISSN:0009-2665.
      A review with 416 refs.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXit1SlsLc%253D&md5=645ba66a869f2f3b93bdde614d1a411f
    6. 6
      Marcus, Y. Chem. Rev. 2009, 109, 1346– 1370
      Google Scholar
      There is no corresponding record for this reference.
    7. 7
      Persson, I. Pure Appl. Chem. 2010, 82, 1901– 1917
      Google Scholar
      There is no corresponding record for this reference.
    8. 8
      Johansson, G. Adv. Inorg. Chem. 1992, 39, 159– 232
      Google Scholar
      8
      Structures of complexes in solution derived from x-ray diffraction measurements
      Johansson, Georg
      Advances in Inorganic Chemistry (1992), 39 (), 159-232CODEN: AICHEP; ISSN:0898-8838.
      A review with 230 refs.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXksFOjur0%253D&md5=50107460acba195ab0b58749c745a14b
    9. 9
      Richens, D. T. The Chemistry of Aqua Ions; Wiley: New York, 1997.
      Google Scholar
      There is no corresponding record for this reference.
    10. 10
      Djamali, E.; Cobble, J. W. J. Phys. Chem. B 2009, 113, 5200– 5207
      Google Scholar
      There is no corresponding record for this reference.
    11. 11
      Smith, D. W. J. Chem. Educ. 1977, 54, 540– 542
      Google Scholar
      There is no corresponding record for this reference.
    12. 12
      Gurney, R. W. Ionic Processes In Solution; McGraw-Hill: NewYork, 1953; Chapter 10.
      Google Scholar
      There is no corresponding record for this reference.
    13. 13
      Smith, J. D.; Cappa, C. D.; Wilson, K. R.; Cohen, R. C.; Geissler, P. L.; Saykally, R. J. Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 14171– 14174
      Google Scholar
      There is no corresponding record for this reference.
    14. 14
      Soper, A. K.; Weckstrom, K. Biophys. Chem. 2006, 124, 180– 191
      Google Scholar
      There is no corresponding record for this reference.
    15. 15
      Stangret, J.; Gampe, T. J. Phys. Chem. A 2002, 106, 5393– 5402
      Google Scholar
      There is no corresponding record for this reference.
    16. 16
      Rodnikova, M. N. Russ. J. Electrochem. 2003, 39, 192– 197
      Google Scholar
      16
      Negative Hydration of Ions
      Rodnikova, M. N.
      Russian Journal of Electrochemistry (Translation of Elektrokhimiya) (2003), 39 (2), 192-197CODEN: RJELE3; ISSN:1023-1935. (MAIK Nauka/Interperiodica Publishing)
      The neg. hydration, that is the increase in the mobility of water mols. near sufficiently large single-charged ions, is studied by modeling, cold-neutron scattering, and computer modeling. Special attention is paid to the mechanism of neg. hydration and the boundary of transition from pos. to neg. and from neg. to hydrophobic hydration. Hypothetical ions with radii of approx. 1.1 and 3.3 Å correspond to these boundaries. Dynamic characteristics of hydration water in these ions are identical to those of water mols. in bulk water.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhtFSntbw%253D&md5=51c3cd958e18c4f97f5632c1d0dc7c47
    17. 17
      Eriksson, A.; Kristiansson, O.; Lindgren, J. J. Mol. Struct. 1984, 114, 455– 458
      Google Scholar
      There is no corresponding record for this reference.
    18. 18
      Kristiansson, O.; Eriksson, A.; Lindgren, J. Acta Chem. Scand., Ser. A 1984, 38, 613– 618
      Google Scholar
      There is no corresponding record for this reference.
    19. 19
      Kristiansson, O.; Lindgren, J.; Devillepin, J. J. Phys. Chem. 1988, 92, 2680– 2685
      Google Scholar
      There is no corresponding record for this reference.
    20. 20
      Kristinansson, O.; Lindgren, J. J. Mol. Struct. 1988, 177, 537– 541
      Google Scholar
      There is no corresponding record for this reference.
    21. 21
      Kristiansson, O.; Lindgren, J. J. Phys. Chem. 1991, 95, 1488– 1493
      Google Scholar
      There is no corresponding record for this reference.
    22. 22
      Bergström, P.; Lindgren, J.; Kristiansson, O. J. Mol. Liq. 1991, 50, 197– 205
      Google Scholar
      There is no corresponding record for this reference.
    23. 23
      Bergström, P.; Lindgren, J.; Kristiansson, O. J. Phys. Chem. 1991, 95, 8575– 8580
      Google Scholar
      There is no corresponding record for this reference.
    24. 24
      Bergström, P.; Lindgren, J.; Sandström, M.; Zhou, Y. Inorg. Chem. 1992, 31, 150– 152
      Google Scholar
      There is no corresponding record for this reference.
    25. 25
      Lindgren, J.; Bergström J. Phys. Chem. 1991, 95, 7650– 7655
      Google Scholar
      There is no corresponding record for this reference.
    26. 26
      Bergström, P.; Lindgren, J. Inorg. Chem. 1992, 31, 1529– 1533
      Google Scholar
      There is no corresponding record for this reference.
    27. 27
      Stangret, J. Spectrosc. Lett. 1988, 21, 369– 381
      Google Scholar
      27
      Solute-affected vibrational spectra of water in calcium perchlorate aqueous solutions
      Stangret, Janusz
      Spectroscopy Letters (1988), 21 (5), 369-81CODEN: SPLEBX; ISSN:0038-7010.
      A method of investigating hydration of a solute (beginning with infinite diln.) with the use of vibrational spectra is presented. The procedure was applied to aq. Ca(ClO4)2 soln. spectra of OD(HDO) fundamental stretching and combination vibrations of H2O (1100-1300 nm). The no. of Ca(ClO4)2-affected H2O mols. was detd.; the obtained hydration spectra revealed anion- and cation-affected H2O bands.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXlsF2iu7o%253D&md5=fcd5e0d6cfecd8760953282f970dde94
    28. 28
      Stangret, J.; Kostrowicki, J. J. Solution Chem. 1988, 17, 165– 173
      Google Scholar
      There is no corresponding record for this reference.
    29. 29
      Stangret, J.; Gampe, T. J. Phys. Chem. B 1999, 103, 3778– 3783
      Google Scholar
      There is no corresponding record for this reference.
    30. 30
      Stangret, J.; Kamieńska-Piotrowicz, E. J. Chem. Soc., Faraday Trans. 1997, 93, 3463– 3466
      Google Scholar
      There is no corresponding record for this reference.
    31. 31
      Śmiechowski, M.; Gojlo, E.; Stangret, J. J. Phys. Chem. B 2004, 108, 15938– 15943
      Google Scholar
      There is no corresponding record for this reference.
    32. 32
      Śmiechowski, M.; Stangret, J. J. Chem. Phys. 2006, 125, 204508(1)– 204508(14)
      Google Scholar
      There is no corresponding record for this reference.
    33. 33
      Śmiechowski, M.; Stangret, J. J. Phys. Chem. A 2007, 111, 2889– 2897
      Google Scholar
      There is no corresponding record for this reference.
    34. 34
      Śmiechowski, M.; Stangret, J. J. Mol. Struct. 2007, 834–836, 239– 248
      Google Scholar
      There is no corresponding record for this reference.
    35. 35
      Smiechowski, M.; Gojlo, E.; Stangret, J. J. Phys. Chem. B 2009, 113, 7650– 7661
      Google Scholar
      There is no corresponding record for this reference.
    36. 36
      Badger, R. M.; Bauer, S. H. J. Chem. Phys. 1937, 5, 839– 852
      Google Scholar
      There is no corresponding record for this reference.
    37. 37
      Shannon, R. Acta Crystallogr., Sect. A 1976, 32, 751– 767
      Google Scholar
      There is no corresponding record for this reference.
    38. 38
      Inorganic Crystal Structure Database; FIZ Karlsruhe: 2009.
      Google Scholar
      There is no corresponding record for this reference.
    39. 39
      Allen, F. Acta Crystallogr., Sect. B 2002, 58, 380– 388
      Google Scholar
      39
      The Cambridge Structural Database: a quarter of a million crystal structures and rising
      Allen, Frank H.
      Acta Crystallographica, Section B: Structural Science (2002), B58 (3, No. 1), 380-388CODEN: ASBSDK; ISSN:0108-7681. (Blackwell Munksgaard)
      The Cambridge Structural Database (CSD) now contains data for more than a quarter of a million small-mol. crystal structures. The information content of the CSD, together with methods for data acquisition, processing and validation, are summarized, with particular emphasis on the chem. information added by CSD editors. Nearly 80% of new structural data arrives electronically, mostly in CIF format, and the CCDC acts as the official crystal structure data depository for 51 major journals. The CCDC now maintains both a CIF archive (more than 73000 CIFs dating from 1996), as well as the distributed binary CSD archive; the availability of data in both archives is discussed. A statistical survey of the CSD is also presented and projections concerning future accession rates indicate that the CSD will contain at least 500000 crystal structures by the year 2010.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XktVOqu74%253D&md5=406cd0df6ea9035a0ebf8dd9eccbd1f8
    40. 40
      Ohtomo, N.; Arakawa, K. Bull. Chem. Soc. Jpn. 1979, 52, 2755– 2759
      Google Scholar
      There is no corresponding record for this reference.
    41. 41
      Bouazizi, S.; Nasr, S. J. Mol. Struct. 2007, 837, 206– 213
      Google Scholar
      There is no corresponding record for this reference.
    42. 42
      Palinkas, G.; Radnai, T.; Hajdu, F. Z. Naturforsch., A: Phys. Sci 1980, 35, 107– 114
      Google Scholar
      42
      Ion-solvent and solvent-solvent interactions. X-ray study of aqueous alkali chloride solutions
      Palinkas, G.; Radnai, T.; Hajdu, F.
      Zeitschrift fuer Naturforschung, Teil A: Astrophysik, Physik und Physikalische Chemie (1980), 35A (1), 107-14CODEN: ZENAAU; ISSN:0044-3166.
      The 1st neighbor model, FNM, used frequently for the description of hydration is modified by dropping the assumption that the structure of the "free" solvent is identical with that of the pure solvent. The modified model, FNM2, reproduces the exptl. x-ray structure functions of alkali chloride solns. quite well and enables the study of perturbed solvent-solvent interactions. The refined structural parameters reasonably indicate the dependence of the hydration of the alkali cations on their radius and concn. The hydration of Cl- is almost independent of both concn. and the type of counter cation. The model assumes regular symmetry for the 1st neighbor coordination sphere, but the high rms deviations of the water-water distances within the shells of the aggregates indicate considerable individual asymmetries.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3cXhtFOgurc%253D&md5=0a43a3433e773b1b6d963589b6081233
    43. 43
      Smirnov, P. R.; Trostin, V. N. Russ. J. Gen. Chem. 2006, 76, 175– 182
      Google Scholar
      43
      Structure of the nearest surrounding of the Li+ ion in aqueous solutions of its salts
      Smirnov, P. R.; Trostin, V. N.
      Russian Journal of General Chemistry (2006), 76 (2), 175-182CODEN: RJGCEK; ISSN:1070-3632. (Pleiades Publishing, Inc.)
      A concise review (87 refs.). Structural characteristics of hydration of lithium ion in aq. solns. of its salts are studied by X-ray diffraction. The results are summarized and correlated with relevant published data obtained by various methods. The structural parameters of the nearest surrounding of the Li+ ion, such as the coordination no., interparticle distances, and types of ionic assocn., are discussed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjtVKnsb4%253D&md5=e7fa28688acda3ac576dc47d18178a33
    44. 44
      Vinogradov, E. V.; Smirnov, P. R.; Trostin, V. N. Russ. Chem. Bull. 2003, 52, 1253– 1271
      Google Scholar
      44
      Structure of hydrated complexes formed by metal ions of Groups I-III of the Periodic Table in aqueous electrolyte solutions under ambient conditions
      Vinogradov, E. V.; Smirnov, P. R.; Trostin, V. N.
      Russian Chemical Bulletin (Translation of Izvestiya Akademii Nauk, Seriya Khimicheskaya) (2003), 52 (6), 1253-1271CODEN: RCBUEY; ISSN:1066-5285. (Kluwer Academic/Consultants Bureau)
      A review. Published and authors exptl. data on the structures of aq. electrolyte solns. under ambient conditions are considered. The hydrated metal complexes formed in aq. solns. are described systematically depending on the size of the cation, the charge, and the structure of the outer electron shell.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXlslSiurw%253D&md5=85d0b574e13ae3a69b6519b45545372c
    45. 45
      Marcus, Y. Chem. Rev. 1988, 88, 1475– 1498
      Google Scholar
      There is no corresponding record for this reference.
    46. 46
      Loeffler, H.; Rode, B. J. Chem. Phys. 2002, 117, 110– 117
      Google Scholar
      There is no corresponding record for this reference.
    47. 47
      Rudolph, W.; Brooker, M.; Pye, C. J. Phys. Chem. 1995, 99, 3793– 3797
      Google Scholar
      There is no corresponding record for this reference.
    48. 48
      Du, H.; Rasaiah, J. C.; Miller, J. D. J. Phys. Chem. B 2007, 111, 209– 217
      Google Scholar
      There is no corresponding record for this reference.
    49. 49
      Novikov, A. G.; Rodnikova, M. N.; Savostin, V. V.; Sobolev, O. V. J. Mol. Liq. 1999, 82, 83– 104
      Google Scholar
      49
      The study of hydration effects in aqueous solutions of LiCl and CsCl by inelastic neutron scattering
      Novikov, A. G.; Rodnikova, M. N.; Savostin, V. V.; Sobolev, O. V.
      Journal of Molecular Liquids (1999), 82 (1,2), 83-104CODEN: JMLIDT; ISSN:0167-7322. (Elsevier Science S.A.)
      Data anal. of inelastic neutron scattering expts. in 2.14M aq. LiCl and CsCl solns. is presented. The diffusion parameters of hydration water mols. (residence time, diffusion coeffs.) were extd. from the quasi-elastic component of the scattering law S(Q,ω). There are about four mols. in the hydration shell of a Li+ ion, and their diffusion mobility is strongly hampered. A Cs+ ion has about 8 mols. in its hydration shell, and this ion intensifies the diffusion motion of surrounding mols. The dynamic hydration nos. were estd.: 3.7 for a Li+ ion and ∼ 1 for a Cs+ ion. The generalized frequency distributions for water mols. hydrating Li+ and Cs+ ions were obtained from the inelastic part of S(Q,ω). The effects obsd. indicate essential distortion of the hydrogen-bond (H-B) network in the vicinity of both ions, but the character of this distortion has different phys. natures.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmtFejsrg%253D&md5=bc22c2ad08854b598aecf0a867f5c151
    50. 50
      Mancinelli, R.; Botti, A.; Bruni, F.; Ricci, M. A.; Soper, A. K. J.Phys. Chem. B 2007, 111, 13570– 13577
      Google Scholar
      There is no corresponding record for this reference.
    51. 51
      Maeda, M.; Ohtaki, H. Bull. Chem. Soc. Jpn. 1975, 48, 3755– 3756
      Google Scholar
      There is no corresponding record for this reference.
    52. 52
      Ohtomo, N.; Arakawa, K. Bull. Chem. Soc. Jpn. 1980, 53, 1789– 1794
      Google Scholar
      There is no corresponding record for this reference.
    53. 53
      Azam, S. S.; Hofer, T. S.; Randolf, B. R.; Rode, B. M. J. Phys. Chem. A 2009, 113, 1827– 1834
      Google Scholar
      There is no corresponding record for this reference.
    54. 54
      Tongraar, A.; Liedl, K. R.; Rode, B. M. J. Phys. Chem. A 1998, 102, 10340– 10347
      Google Scholar
      There is no corresponding record for this reference.
    55. 55
      Heinje, G.; Luck, W.; Heinzinger, K. J. Phys. Chem. 1987, 91, 331– 338
      Google Scholar
      There is no corresponding record for this reference.
    56. 56
      Bosi, P.; Felici, R.; Rongoni, E.; Sacchetti, F. Nuovo Cimento Soc. Ital. Fis., D 1984, 3, 1029– 1038
      Google Scholar
      56
      On the structure of alkali halide solutions. II. - Neutron and x-ray diffraction
      Bosi, P.; Felici, R.; Rongoni, E.; Sacchetti, F.
      Nuovo Cimento della Societa Italiana di Fisica, D: Condensed Matter, Atomic, Molecular and Chemical Physics, Fluids, Plasmas, Biophysics (1984), 3D (6), 1029-38CODEN: NCSDDN; ISSN:0392-6737.
      The structure factors of NaI solns. in D2O and H2O were detd. by using both neutron and x-ray scattering. The results were analyzed in terms of the structures of the hydration spheres of both Na+ and I- ions. No concn. or temp. dependences of the size of the hydration shells were found; whereas the structure of the free water appeared to be affected, at least at small distances.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXltlOnu7s%253D&md5=bcab336fdb57ba31006c71b72be4131b
    57. 57
      Ohtaki, H.; Fukushima, N. J. Solution Chem. 1992, 21, 23– 38
      Google Scholar
      There is no corresponding record for this reference.
    58. 58
      Chizhik, V. I.; Mikhailov, V. I.; Su, P. C. Theor. Exp. Chem. 1987, 22, 480– 483
      Google Scholar
      There is no corresponding record for this reference.
    59. 59
      Smirnov, P. R.; Trostin, V. N. Russ. J. Gen. Chem. 2007, 77, 2101– 2107
      Google Scholar
      59
      Structures of the nearest surroundings of the K+, Rb+, and Cs+ ions in aqueous solutions of their salts
      Smirnov, P. R.; Trostin, V. N.
      Russian Journal of General Chemistry (2007), 77 (12), 2101-2107CODEN: RJGCEK; ISSN:1070-3632. (Pleiades Publishing, Ltd.)
      A review is presented considering the published data on structural characteristics of hydration of K+, Rb+, and Cs+ ions in aq. solns. of their salts under std. conditions. The structural parameters of the nearest surrounding of the K+, Rb+, and Cs+ ions, such as the coordination nos., interparticle distances, and types of ionic assocn., are discussed. It is noted that, because of weak tendency of these cations to hydration, the parameters of their coordination spheres strongly depend on the concn. and chem. nature of counterions.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsFantbo%253D&md5=6ba79dc79f373f102e0b774cbf8f50c0
    60. 60
      Nikologorskaya, E. L.; Kuznetsov, V. V.; Grechin, O. V.; Trostin, V. N. Russ. J. Inorg. Chem. 2000, 45, 1759– 1766
      Google Scholar
      There is no corresponding record for this reference.
    61. 61
      D’Angelo, P.; Persson, I. Inorg. Chem. 2004, 43, 3543– 3549
      Google Scholar
      There is no corresponding record for this reference.
    62. 62
      Ohkubo, T.; Konishi, T.; Hattori, Y.; Kanoh, H.; Fujikawa, T.; Kaneko, K. J. Am. Chem. Soc. 2002, 124, 11860– 11861
      Google Scholar
      There is no corresponding record for this reference.
    63. 63
      Kubozono, Y.; Hirano, A.; Maeda, H.; Kashino, S.; Emura, S.; Ishida, H. Z. Naturforsch., Teil A 1994, 49, 727– 729
      Google Scholar
      63
      An EXAFS investigation of local structure around Rb+ in aqueous solution
      Kubozono, Yoshihiro; Hirano, Akiko; Maeda, Hironobu; Kashino, Setsuo; Emura, Shuichi; Ishida, Hiroyuki
      Zeitschrift fuer Naturforschung, A: Physical Sciences (1994), 49 (6), 727-9CODEN: ZNASEI; ISSN:0932-0784.
      The Rb+ is surrounded by ca. six O atoms of H2O mols. with Rb-O distance 2.90 (3) Å. The coordination no. and Rb-O distance compare well with those for alk.-metal ions estd. by x-ray diffraction.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXkvFamtL4%253D&md5=0675858b60155b558694b4220695536a
    64. 64
      Ramos, S.; Barnes, A. C.; Neilson, G. W.; Capitan, M. J. Chem. Phys. 2000, 258, 171– 180
      Google Scholar
      There is no corresponding record for this reference.
    65. 65
      San-Román, M. L.; Hernández-Cobos, J.; Saint-Martin, H.; Ortega-Blake, I. Theor. Chem. Acc. 2009, 126, 197– 211
      Google Scholar
      There is no corresponding record for this reference.
    66. 66
      Hofer, T. S.; Randolf, B. R.; Rode, B. M. J. Comput. Chem. 2005, 26, 949– 956
      Google Scholar
      There is no corresponding record for this reference.
    67. 67
      Tamura, Y.; Yamaguchi, T.; Okada, I.; Ohtaki, H. Z. Naturforsch., Teil A 1987, 42, 367– 376
      Google Scholar
      67
      An x-ray diffraction study on the structure of concentrated aqueous caesium iodide and lithium iodide solutions
      Tamura, Yusuke; Yamaguchi, Toshio; Okada, Isao; Ohtaki, Hitoshi
      Zeitschrift fuer Naturforschung, A: Physical Sciences (1987), 42 (4), 367-76CODEN: ZNASEI; ISSN:0932-0784.
      The hydration structures of 2.78 and 5.56 mol CsI and 2.78 and 6.05 mol LiI solns. were studied by x-ray scattering at 293 and 343 K. Differences in the radial distribution functions (DRDFs) were obsd. between the CsI and LiI solns. of similar compns. The DRDFs showed a peak arising from Cs-I contact-ion-pairs at 390 pm for all CsI solns. The effects of the concn. and the temp. on the formation of ion-pairs and on the hydration structure of the ions are discussed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2sXkt1ylurc%253D&md5=f41a6b9fc7867a09ab8e201f11b2a913
    68. 68
      Schwenk, C. F.; Hofer, T. S.; Rode, B. M. J. Phys. Chem. A 2004, 108, 1509– 1514
      Google Scholar
      There is no corresponding record for this reference.
    69. 69
      Mile, V.; Pusztai, L.; Dominguez, H.; Pizio, O. J. Phys. Chem. B 2009, 113, 10760– 10769
      Google Scholar
      There is no corresponding record for this reference.
    70. 70
      Smirnov, P.; Trostin, V. Russ. J. Gen. Chem. 2007, 77, 844– 850
      Google Scholar
      70
      Structure of the nearest surrounding of the Na+ ion in aqueous solutions of its salts
      Smirnov, P. R.; Trostin, V. N.
      Russian Journal of General Chemistry (2007), 77 (5), 844-850CODEN: RJGCEK; ISSN:1070-3632. (Pleiades Publishing, Ltd.)
      Published data obtained by various research methods on structural characteristics of sodium ion hydration in aq. solns. of its salts and authors, x-ray diffraction data were generalized. Structural parameters of the nearest surrounding of Na+ ion, such as its coordination no., interparticle distances, and types of ion assocn., were discussed. The coordination no. of the cation changes from 4 to 6 upon diln. of the solns.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntFyisrg%253D&md5=c569711ce10deab00ac9f85043e85da2
    71. 71
      Helm, L.; Merbach, A. E. Coord. Chem. Rev. 1999, 187, 151– 181
      Google Scholar
      There is no corresponding record for this reference.
    72. 72
      Persson, I.; Sandström, M.; Yokoyama, H.; Chaudhry, M. Z. Naturforsch., Teil A 1995, 50, 21– 37
      Google Scholar
      72
      Structure of the solvated strontium and barium ions in aqueous, dimethyl sulfoxide and pyridine solution, and crystal structure of strontium and barium hydroxide octahydrate
      Persson, Ingmar; Sandstroem, Magnus; Yokoyama, Haruhiko; Chaudhry, Monika
      Zeitschrift fuer Naturforschung, A: Physical Sciences (1995), 50 (1), 21-37CODEN: ZNASEI; ISSN:0932-0784. (Verlag der Zeitschrift fuer Naturforschung)
      Single crystal x-ray data, collected at 298 K, are used to re-det. the crystal structure of the non-isomorphic compds. [Sr(H2O)8](OH)2 and [Ba(H2O)8](OH)2. The eight water oxygen atoms form distorted Archimedean anti-prisms around the octahydrated metal ions with mean metal ion-oxygen distances 2.62 and 2.79 Å for strontium and barium, resp. A second coordination shell of 24 hydrogen-bonded oxygen atoms with mean metal ion-oxygen distances M...OII 4.76 and 4.80 Å, resp., is obsd. The hydroxide ions in both structures have an unusual hydrogen bond arrangement with 5 bonds accepted and one donated. The structure of the solvated strontium and barium ions in aq., DMSO and pyridine solns. has been studied by means of large angle x-ray scattering and extended X-ray absorption fine structure spectroscopy techniques. In aq. soln. independent detns. of the first-sphere metal-oxygen coordination by the two techniques resulted in the bond lengths Sr-O 2.63(2) and Ba-O 2.81(3) Å, and for both metal ions a hydration no. of 8.1(3). The second coordination spheres are very diffuse with only about 13 water mols. at similar M...OII distances as in the crystal structures and 2-3 water mols. closer to the metal ions. In DMSO soln. both ions were found to coordinate 6.0(5) solvent mols. with the distances Sr-O 2.54(1), Sr...S 3.77(1) Å, and Ba-O 2.76(1), Ba...S 3.99 (1) Å. For the solvated ions in pyridine soln. EXAFS measurements yielded the distances Sr-N 2.57(2) and Ba-N 2.78(3) Å, with a probable solvation no. of 6. Correlations of hydration enthalpies and partial molar volumes with exptl. M-O bond distances in aq. soln. are used to discuss hydration nos. and bond character for all of the alk. earth metal ions.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXjvVyqtLc%253D&md5=3edb58bc4a184f100000600fc4722b41
    73. 73
      Calligaris, M. Coord. Chem. Rev. 2004, 248, 351– 375
      Google Scholar
      There is no corresponding record for this reference.
    74. 74
      Stålhandske, C. M. V.; Persson, I.; Sandström, M.; Kamienska-Piotrowicz, E. Inorg. Chem. 1997, 36, 3174– 3182
      Google Scholar
      There is no corresponding record for this reference.
    75. 75
      Johansson, G.; Sandström, M. Chem. Scr. 1973, 4, 195– 198
      Google Scholar
      75
      Computer programs for the analysis of data on x-ray diffraction by liquids
      Johansson, Georg; Sandstrom, Magnus
      Chemica Scripta (1973), 4 (5), 195-8CODEN: CSRPB9; ISSN:0004-2056.
      A short description is given of a set of computer programs, KURVLR and PUTSLR, which can be used for the treatment and anal. of data on x-ray scattering by liqs. and amorphous substances. The programs are extended versions, written in FORTRAN IV. By the KURVLR program, obsd. intensity data can be converted to radial distribution functions, and theor. intensities and peak shapes can be calcd. for assumed mol. models. By PUTSLR a refinement of parameters in the model can be carried out by means of a least squares procedure in which exptl. and theor. calcd. intensities are compared.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2cXmsVKgsQ%253D%253D&md5=495bed1fbcd660c6e650a37ee9871975
    76. 76
      Cromer, D. J. Chem. Phys. 1969, 50, 4857– 4859
      Google Scholar
      There is no corresponding record for this reference.
    77. 77
      Cromer, D.; Mann, J. J. Chem. Phys. 1967, 47, 1892– 1893
      Google Scholar
      There is no corresponding record for this reference.
    78. 78
      Molund, M.; Persson, I. Chem. Scr. 1985, 25, 197– 197
      Google Scholar
      78
      STEPLR - a program for refinements of data on x-ray scattering by liquids
      Molund, Mary; Persson, Ingmar
      Chemica Scripta (1985), 25 (2), 197CODEN: CSRPB9; ISSN:0004-2056.
      The STEPLR program for least-squares refinements of data on x-ray scattering by liqs. simplifies interactive runs at a computer terminal and requires considerably less input data than the previous program. A new subroutine, SCATF, which contains scattering factors, values for the real and the imaginary part of the anomalous dispersion, and incoherent scattering factors for a large no. of neutral atoms, is reported.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2MXls12hsLY%253D&md5=1983481e270866c1f2844865b5bff365
    79. 79
      Levy, H. A.; Danford, M. D.; Narten, A. H. Data Collection and Evaluation with an X-Ray Diffractometer Designed for the Study of Liquid Structure; Oak Ridge National Laboratory: Oak Ridge, TN, 1966.
      Google Scholar
      There is no corresponding record for this reference.
    80. 80
      Beattie, J. K.; Best, S. P.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 1981, 2105– 2111
      Google Scholar
      There is no corresponding record for this reference.
    81. 81
      Andrade-López, N.; Cartas-Rosado, R.; García-Baéz, E.; Contreras, R.; Tlahuext, H. Heteroat. Chem. 1998, 9, 399– 409
      Google Scholar
      81
      Boron heterocycles derived from 2-guanidinobenzimidazole
      Andrade-Lopez, Noemi; Cartas-Rosado, Rocio; Garcia-Baez, Efren; Contreras, Rosalinda; Tlahuext, Hugo
      Heteroatom Chemistry (1998), 9 (4), 399-409CODEN: HETCE8; ISSN:1042-7163. (John Wiley & Sons, Inc.)
      The syntheses and structure detns. of a series of boron heterocycles derived from 2-guanidinobenzimidazole I (R = H, Me) are reported. Structures of new compds., 2-guanidino-1-methyl-benzimidazole (I; R = Me), diphenyl(2-guanidinobenzimidazole-N,N')borates II (R = H, Me, R1 = Ph), (hydroxy)(phenyl)(2-guanidinobenzimidazole-N,N')borates (R = H, Me, R1 = OH), (alkoxy)(phenyl)(2-guanidinobenzimidazole-N,N')borates II (R = H, R1 = MeO, Me2CHO, AcO; R = Me, R1 = MeO), dihydroxy(2-guanidino-1-methyl-benzimidazole-N,N')borate, difluoro(2-guanidinobenzimidazole-N,N')borate, dihydroxy(2-guanidino-1-benzimidazole-N,N')borate potassium salt (III), diphenyl(2-guanidinium-10H-benzimidazole-N,N')borate chloride, (methoxy)(phenyl)(2-guanidinium-10H-benzimidazole-N,N')borate chloride (IV), and N10-borane-(diphenyl-2-guanidinobenzimidazole-N,N')borate, were detd. based on 1H, 13C, 15N, and 11B spectroscopy. The x-ray diffraction structures of II (R = H, Me, R1 = Ph, OH; R = H, R1 = MeO), III, and IV were obtained. The formation of N3-borane adducts derived from I, and the dihydrido-(2-guanidinobenzimidazole-N,N')borate and dihydrido-(2-guanidino-1-methyl-benzimidazole-N,N')borate were obsd. by 11B NMR. The results show that 2-guanidinobenzimidazole gives stable borate heterocycles with a delocalized π electronic system. A dynamic exchange of N-H protons was obsd. with preferred protonation at N-12. The new heterocycles are protonated at N-10 by acidic substances to give pyridinium-type heterocycles or can lose a proton to give iminium salts.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXjs12rtL0%253D&md5=a303e6aeb847b4d8481b5043f7871e89
    82. 82
      Huheey, J. E.; Keiter, E. A.; Keiter, R. L. I. Inorganic Chemistry: Principles of Structure and Reactivity, 4th ed.; Prentice Hall: 1997; pp 122– 127.
      Google Scholar
      There is no corresponding record for this reference.
    83. 83
      Lundberg, D.; Persson, I.; Eriksson, L.; D’Angelo, P.; De Panfilis, S. Inorg. Chem. 2010, 49, 4420– 4432
      Google Scholar
      There is no corresponding record for this reference.
    84. 84
      Becker, M.; Förster, C.; Franzen, C.; Hartrath, J.; Kirsten, E.; Knuth, J.; Klinkhammer, K. W.; Sharma, A.; Hinderberger, D. Inorg. Chem. 2008, 47, 9965– 9978
      Google Scholar
      84
      Persistent Radicals of Trivalent Tin and Lead
      Becker, Marco; Foerster, Christoph; Franzen, Christian; Hartrath, Johannes; Kirsten, Enzio; Knuth, Jorn; Klinkhammer, Karl W.; Sharma, Ajay; Hinderberger, Dariush
      Inorganic Chemistry (2008), 47 (21), 9965-9978CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)
      The authors present synthetic, crystallog., and new EPR spectroscopic work that shows that the synthetic route leading to the recently reported, 1st persistent plumbyl radical •PbEbt3 (Ebt = ethylbis(trimethylsilyl)silyl), i.e., the oxidn. of the related PbEbt3-anion, was easily extended to the synthesis of other persistent mol. mononuclear radicals of Pb and Sn. At 1st, various novel solvates of homoleptic K metalates KSnHyp3 (4a), KPbHyp3 (3a), KSnEbt3 (4b), KPbIbt3 (3c), and KSnIbt3 (4c) (Hyp = tris(trimethylsilyl)silyl, Ibt = isopropylbis(trimethylsilyl)silyl), as well as some heteroleptic metalates, such as [Li(OEt2)2][SnBuHyp2] (3d), [Li(OEt2)2][PbBuHyp2] (4d), [Li(THF)4][PbPhHyp2] (3e), and [K(THF)7][PbHyp2{N(SiMe3)2}] (3f), were synthesized and crystallog. characterized. Through oxidn. by Sn(II) and Pb(II) bis(trimethylsilyl)amides or the related 2,6-di-tert-butylphenoxides, they were oxidized to yield in most cases the corresponding radicals. Five novel persistent homoleptically substituted radicals, i.e., •SnHyp3 (2a), •PbHyp3 (1a), •SnEbt3 (2b), •SnIbt3 (2c), and •PbIbt3 (1c), were characterized by EPR spectroscopy. The stannyl radicals 2a and 2c as well as the plumbyl radical 1c were isolated as intensely colored cryst. compds. and were characterized by x-ray diffraction. Persistent heteroleptically substituted radicals such as •PbHyp2Ph (1e) or •PbHyp2Et (1g) were also generated, and some selected EPR data are given for comparison. The plumbyl radicals •PbR3 exhibit a clean monomol. decay leading to the release of a temp.-dependent stationary concn. of branched silyl radicals. They may thus serve as tunable sources of these reactive species that may be used as reagents for mild radical silylations and/or as initiators for radical polymns. The authors present EPR-spectroscopic studies for the new Sn- and Pb-contg. compds. giving detailed insights into their electronic and geometric structure in soln., as well as structural studies on the cryst. state of the radicals, some of their anionic precursors, and some side-products.
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    85. 85
      Lindgren, J.; Kristiansson, O.; Paluszkiewicz, C. In Interactions of Water in Ionic and Non-ionic Hydrates; Springer-Verlag: Berlin Heidelberg, 1987; pp 43– 46.
      Google Scholar
      There is no corresponding record for this reference.

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